diff --git a/Frends.HTTP.DownloadFile/CHANGELOG.md b/Frends.HTTP.DownloadFile/CHANGELOG.md
index 597e1b9..20f6d39 100644
--- a/Frends.HTTP.DownloadFile/CHANGELOG.md
+++ b/Frends.HTTP.DownloadFile/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## [1.4.0] - 2025-11-18
+### Added
+- Added CertificateStoreLocation option to allow selection between CurrentUser and LocalMachine certificate stores when using certificate authentication.
+
 ## [1.3.0] - 2025-05-15
 ### Changed
 - Added new Overwrite parameter to control whether the downloaded file should replace an existing one.
diff --git a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/Frends.HTTP.DownloadFile.Tests.csproj b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/Frends.HTTP.DownloadFile.Tests.csproj
index 40a3537..9163594 100644
--- a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/Frends.HTTP.DownloadFile.Tests.csproj
+++ b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/Frends.HTTP.DownloadFile.Tests.csproj
@@ -13,6 +13,7 @@
 		<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
 	</PackageReference>
 	<PackageReference Include="Pluralsight.Crypto" Version="1.1.0" />
+	<PackageReference Include="RichardSzalay.MockHttp" Version="7.0.0" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/UnitTests.cs b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/UnitTests.cs
index 00db7d0..cfb392a 100644
--- a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/UnitTests.cs
+++ b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.Tests/UnitTests.cs
@@ -1,11 +1,12 @@
 using Frends.HTTP.DownloadFile.Definitions;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
-using Pluralsight.Crypto;
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Security.Cryptography;
 using System.Security.Cryptography.X509Certificates;
 using System.Threading.Tasks;
+using Pluralsight.Crypto;
 
 namespace Frends.HTTP.DownloadFile.Tests;
 
@@ -14,7 +15,9 @@ public class UnitTests
 {
     private static readonly string _directory = Path.Combine(Environment.CurrentDirectory, "testfiles");
     private static readonly string _filePath = Path.Combine(_directory, "picture.jpg");
-    private static readonly string _targetFileAddress = @"https://upload.wikimedia.org/wikipedia/commons/thumb/2/2f/Google_2015_logo.svg/1200px-Google_2015_logo.svg.png";
+
+    private static readonly string _targetFileAddress =
+        "https://frendsfonts.blob.core.windows.net/images/frendsLogo.png";//@"http://localhost:9999/testfile.png";
     private readonly string _certificatePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "TestFiles", "certwithpk.pfx");
     private readonly string _privateKeyPassword = "password";
 
@@ -138,9 +141,21 @@ public async Task TestFileDownload_WithHeaders()
     {
         var headers = new[] { new Header() { Name = "foo", Value = "bar" } };
 
-        var auths = new List<Authentication>() { Authentication.None, Authentication.Basic, Authentication.WindowsAuthentication, Authentication.WindowsIntegratedSecurity, Authentication.OAuth };
+        var auths = new List<Authentication>
+        {
+            Authentication.None,
+            Authentication.Basic,
+            Authentication.WindowsAuthentication,
+            Authentication.WindowsIntegratedSecurity,
+            Authentication.OAuth
+        };
 
-        var certSource = new List<CertificateSource>() { CertificateSource.CertificateStore, CertificateSource.File, CertificateSource.String };
+        var certSource = new List<CertificateSource>
+        {
+            CertificateSource.CertificateStore,
+            CertificateSource.File,
+            CertificateSource.String
+        };
 
         var input = new Input
         {
@@ -188,7 +203,12 @@ public async Task TestFileDownload_WithHeaders()
     [TestMethod]
     public async Task TestFileDownload_Certification()
     {
-        var certSources = new List<CertificateSource>() { CertificateSource.File, CertificateSource.String, CertificateSource.CertificateStore };
+        var certSources = new List<CertificateSource>
+        {
+            CertificateSource.File,
+            CertificateSource.String,
+            CertificateSource.CertificateStore
+        };
 
         var input = new Input
         {
@@ -328,4 +348,339 @@ public async Task TestFileDownload_WithOverwriteTrue_ShouldOverwriteExistingFile
         var actualContent = File.ReadAllText(_filePath);
         Assert.AreNotEqual("OLD CONTENT", actualContent, "File should have been overwritten.");
     }
+
+    [TestMethod]
+    [ExpectedException(typeof(ArgumentNullException))]
+    public async Task TestFileDownload_WithEmptyUrl_ShouldThrowException()
+    {
+        var input = new Input
+        {
+            Url = "",
+            FilePath = _filePath,
+            Headers = null
+        };
+
+        var options = new Options
+        {
+            AllowInvalidCertificate = true,
+            Authentication = Authentication.None,
+            ConnectionTimeoutSeconds = 60
+        };
+
+        await HTTP.DownloadFile(input, options, default);
+    }
+
+    [TestMethod]
+    public async Task TestFileDownload_WithCertificateStoreLocation_CurrentUser()
+    {
+        var tp = CertificateHandler(_certificatePath, _privateKeyPassword, false, null);
+
+        var input = new Input
+        {
+            Url = _targetFileAddress,
+            FilePath = _filePath,
+            Headers = null
+        };
+
+        var options = new Options
+        {
+            AllowInvalidCertificate = true,
+            AllowInvalidResponseContentTypeCharSet = true,
+            Authentication = Authentication.ClientCertificate,
+            AutomaticCookieHandling = true,
+            CertificateThumbprint = tp,
+            ClientCertificateFilePath = _certificatePath,
+            ClientCertificateInBase64 = "",
+            ClientCertificateKeyPhrase = _privateKeyPassword,
+            ClientCertificateSource = CertificateSource.CertificateStore,
+            CertificateStoreLocation = CertificateStoreLocation.CurrentUser,
+            ConnectionTimeoutSeconds = 60,
+            FollowRedirects = true,
+            LoadEntireChainForCertificate = false,
+            Password = "",
+            ThrowExceptionOnErrorResponse = true,
+            Token = "",
+            Username = "domain\\username"
+        };
+
+        var result = await HTTP.DownloadFile(input, options, default);
+
+        Assert.IsNotNull(result);
+        Assert.IsTrue(result.Success);
+        Assert.IsNotNull(result.FilePath);
+        Assert.IsTrue(File.Exists(result.FilePath));
+
+        CertificateHandler(_certificatePath, _privateKeyPassword, true, tp);
+    }
+
+    [TestMethod]
+    [ExpectedException(typeof(Exception))]
+    public async Task TestFileDownload_WithCertificateStoreLocation_LocalMachine_NotFound()
+    {
+        // Use real HTTP client factory to test certificate lookup failure
+        HTTP.ClientFactory = new HttpClientFactory();
+
+        var input = new Input
+        {
+            Url = _targetFileAddress,
+            FilePath = _filePath,
+            Headers = null
+        };
+
+        var options = new Options
+        {
+            AllowInvalidCertificate = true,
+            AllowInvalidResponseContentTypeCharSet = true,
+            Authentication = Authentication.ClientCertificate,
+            AutomaticCookieHandling = true,
+            CertificateThumbprint = "NONEXISTENTTHUMBPRINT",
+            ClientCertificateFilePath = "",
+            ClientCertificateInBase64 = "",
+            ClientCertificateKeyPhrase = "",
+            ClientCertificateSource = CertificateSource.CertificateStore,
+            CertificateStoreLocation = CertificateStoreLocation.LocalMachine,
+            ConnectionTimeoutSeconds = 60,
+            FollowRedirects = true,
+            LoadEntireChainForCertificate = false,
+            Password = "",
+            ThrowExceptionOnErrorResponse = true,
+            Token = "",
+            Username = "domain\\username"
+        };
+
+        await HTTP.DownloadFile(input, options, default);
+    }
+
+    [TestMethod]
+    public async Task TestFileDownload_WithOverwriteFalse_ExistingFile_ShouldThrow()
+    {
+        File.WriteAllText(_filePath, "OLD CONTENT");
+
+        var input = new Input
+        {
+            Url = _targetFileAddress,
+            FilePath = _filePath,
+            Headers = null
+        };
+
+        var options = new Options
+        {
+            AllowInvalidCertificate = true,
+            AllowInvalidResponseContentTypeCharSet = true,
+            Authentication = Authentication.None,
+            AutomaticCookieHandling = true,
+            CertificateThumbprint = "",
+            ClientCertificateFilePath = "",
+            ClientCertificateInBase64 = "",
+            ClientCertificateKeyPhrase = "",
+            ClientCertificateSource = CertificateSource.File,
+            ConnectionTimeoutSeconds = 60,
+            FollowRedirects = true,
+            LoadEntireChainForCertificate = true,
+            Password = "",
+            ThrowExceptionOnErrorResponse = true,
+            Token = "",
+            Username = "domain\\username",
+            Overwrite = false
+        };
+
+        await Assert.ThrowsExceptionAsync<Exception>(async () =>
+            await HTTP.DownloadFile(input, options, default));
+    }
+
+    [TestMethod]
+    [ExpectedException(typeof(Exception))]
+    public async Task TestFileDownload_WindowsAuth_InvalidUsername_ShouldThrow()
+    {
+        // Use real HTTP client factory to test username validation
+        HTTP.ClientFactory = new HttpClientFactory();
+
+        var input = new Input
+        {
+            Url = _targetFileAddress,
+            FilePath = _filePath,
+            Headers = null
+        };
+
+        var options = new Options
+        {
+            AllowInvalidCertificate = true,
+            AllowInvalidResponseContentTypeCharSet = true,
+            Authentication = Authentication.WindowsAuthentication,
+            AutomaticCookieHandling = true,
+            CertificateThumbprint = "",
+            ClientCertificateFilePath = "",
+            ClientCertificateInBase64 = "",
+            ClientCertificateKeyPhrase = "",
+            ClientCertificateSource = CertificateSource.File,
+            ConnectionTimeoutSeconds = 60,
+            FollowRedirects = true,
+            LoadEntireChainForCertificate = false,
+            Password = "password",
+            ThrowExceptionOnErrorResponse = true,
+            Token = "",
+            Username = "invalid_username_without_domain"
+        };
+
+        await HTTP.DownloadFile(input, options, default);
+    }
+
+    [TestMethod]
+    public async Task TestFileDownload_CertificateFromFile_WithoutKeyPhrase()
+    {
+        var tp = CertificateHandler(_certificatePath, _privateKeyPassword, false, null);
+
+        var input = new Input
+        {
+            Url = _targetFileAddress,
+            FilePath = _filePath,
+            Headers = null
+        };
+
+        var options = new Options
+        {
+            AllowInvalidCertificate = true,
+            AllowInvalidResponseContentTypeCharSet = true,
+            Authentication = Authentication.ClientCertificate,
+            AutomaticCookieHandling = true,
+            CertificateThumbprint = "",
+            ClientCertificateFilePath = _certificatePath,
+            ClientCertificateInBase64 = "",
+            ClientCertificateKeyPhrase = _privateKeyPassword,
+            ClientCertificateSource = CertificateSource.File,
+            ConnectionTimeoutSeconds = 60,
+            FollowRedirects = true,
+            LoadEntireChainForCertificate = false,
+            Password = "",
+            ThrowExceptionOnErrorResponse = true,
+            Token = "",
+            Username = "domain\\username"
+        };
+
+        var result = await HTTP.DownloadFile(input, options, default);
+
+        Assert.IsNotNull(result);
+        Assert.IsTrue(result.Success);
+
+        CertificateHandler(_certificatePath, _privateKeyPassword, true, tp);
+    }
+
+    [TestMethod]
+    public async Task TestFileDownload_CertificateFromString_WithKeyPhrase()
+    {
+        var tp = CertificateHandler(_certificatePath, _privateKeyPassword, false, null);
+
+        var input = new Input
+        {
+            Url = _targetFileAddress,
+            FilePath = _filePath,
+            Headers = null
+        };
+
+        var options = new Options
+        {
+            AllowInvalidCertificate = true,
+            AllowInvalidResponseContentTypeCharSet = true,
+            Authentication = Authentication.ClientCertificate,
+            AutomaticCookieHandling = true,
+            CertificateThumbprint = "",
+            ClientCertificateFilePath = "",
+            ClientCertificateInBase64 = Convert.ToBase64String(File.ReadAllBytes(_certificatePath)),
+            ClientCertificateKeyPhrase = _privateKeyPassword,
+            ClientCertificateSource = CertificateSource.String,
+            ConnectionTimeoutSeconds = 60,
+            FollowRedirects = true,
+            LoadEntireChainForCertificate = false,
+            Password = "",
+            ThrowExceptionOnErrorResponse = true,
+            Token = "",
+            Username = "domain\\username"
+        };
+
+        var result = await HTTP.DownloadFile(input, options, default);
+
+        Assert.IsNotNull(result);
+        Assert.IsTrue(result.Success);
+
+        CertificateHandler(_certificatePath, _privateKeyPassword, true, tp);
+    }
+
+    [TestMethod]
+    public async Task TestFileDownload_WithNullHeaders()
+    {
+        var input = new Input
+        {
+            Url = _targetFileAddress,
+            FilePath = _filePath,
+            Headers = null
+        };
+
+        var options = new Options
+        {
+            AllowInvalidCertificate = true,
+            AllowInvalidResponseContentTypeCharSet = true,
+            Authentication = Authentication.Basic,
+            AutomaticCookieHandling = true,
+            CertificateThumbprint = "",
+            ClientCertificateFilePath = "",
+            ClientCertificateInBase64 = "",
+            ClientCertificateKeyPhrase = "",
+            ClientCertificateSource = CertificateSource.File,
+            ConnectionTimeoutSeconds = 60,
+            FollowRedirects = true,
+            LoadEntireChainForCertificate = false,
+            Password = "password",
+            ThrowExceptionOnErrorResponse = false,
+            Token = "",
+            Username = "domain\\username"
+        };
+
+        var result = await HTTP.DownloadFile(input, options, default);
+
+        Assert.IsNotNull(result);
+        Assert.IsTrue(result.Success);
+    }
+
+    [TestMethod]
+    public async Task TestFileDownload_CachedClient()
+    {
+        var input = new Input
+        {
+            Url = _targetFileAddress,
+            FilePath = _filePath,
+            Headers = null
+        };
+
+        var options = new Options
+        {
+            AllowInvalidCertificate = true,
+            AllowInvalidResponseContentTypeCharSet = true,
+            Authentication = Authentication.None,
+            AutomaticCookieHandling = true,
+            CertificateThumbprint = "",
+            ClientCertificateFilePath = "",
+            ClientCertificateInBase64 = "",
+            ClientCertificateKeyPhrase = "",
+            ClientCertificateSource = CertificateSource.File,
+            ConnectionTimeoutSeconds = 60,
+            FollowRedirects = true,
+            LoadEntireChainForCertificate = false,
+            Password = "",
+            ThrowExceptionOnErrorResponse = false,
+            Token = "",
+            Username = ""
+        };
+
+        // First request creates client
+        var result1 = await HTTP.DownloadFile(input, options, default);
+        Assert.IsTrue(result1.Success);
+
+        // Cleanup and recreate directory for second request
+        Cleanup();
+        Directory.CreateDirectory(_directory);
+
+        // Second request should use cached client
+        var result2 = await HTTP.DownloadFile(input, options, default);
+        Assert.IsTrue(result2.Success);
+    }
 }
\ No newline at end of file
diff --git a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Definitions/CertificateStoreLocation.cs b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Definitions/CertificateStoreLocation.cs
new file mode 100644
index 0000000..83cfeb7
--- /dev/null
+++ b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Definitions/CertificateStoreLocation.cs
@@ -0,0 +1,16 @@
+namespace Frends.HTTP.DownloadFile.Definitions;
+
+/// <summary>
+/// Certificate store location.
+/// </summary>
+public enum CertificateStoreLocation
+{
+    /// <summary>
+    /// The X.509 certificate store assigned to the current user.
+    /// </summary>
+    CurrentUser,
+    /// <summary>
+    /// The X.509 certificate store assigned to the local machine.
+    /// </summary>
+    LocalMachine
+}
diff --git a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Definitions/Options.cs b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Definitions/Options.cs
index d2d70a0..9bb7b41 100644
--- a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Definitions/Options.cs
+++ b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Definitions/Options.cs
@@ -81,6 +81,15 @@ public class Options
     [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
     public string CertificateThumbprint { get; set; }
 
+    /// <summary>
+    /// Applicable only when Certificate Source is "CertificateStore".
+    /// Store location for the certificate.
+    /// </summary>
+    /// <example>CurrentUser</example>
+    [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
+    [DefaultValue(CertificateStoreLocation.CurrentUser)]
+    public CertificateStoreLocation CertificateStoreLocation { get; set; }
+
     /// <summary>
     /// Should the entire certificate chain be loaded from the certificate store and included in the request. Only valid when using Certificate Store as the Certificate Source 
     /// </summary>
diff --git a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Extensions.cs b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Extensions.cs
index 3ab6b87..1bc35f0 100644
--- a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Extensions.cs
+++ b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Extensions.cs
@@ -54,7 +54,7 @@ private static X509Certificate[] GetCertificates(Options options)
         {
             case CertificateSource.CertificateStore:
                 var thumbprint = options.CertificateThumbprint;
-                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate);
+                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate, options.CertificateStoreLocation);
                 break;
             case CertificateSource.File:
                 certificates = GetCertificatesFromFile(options.ClientCertificateFilePath, options.ClientCertificateKeyPhrase);
@@ -94,14 +94,21 @@ private static X509Certificate2[] GetCertificatesFromFile(string clientCertifica
     }
 
     private static X509Certificate2[] GetCertificatesFromStore(string thumbprint,
-        bool loadEntireChain)
+        bool loadEntireChain, CertificateStoreLocation storeLocation)
     {
         thumbprint = Regex.Replace(thumbprint, @"[^\da-zA-z]", string.Empty).ToUpper();
-        using var store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
+        var location = storeLocation == CertificateStoreLocation.CurrentUser
+            ? StoreLocation.CurrentUser
+            : StoreLocation.LocalMachine;
+        var locationText = storeLocation == CertificateStoreLocation.CurrentUser
+            ? "current user"
+            : "local machine";
+
+        using var store = new X509Store(StoreName.My, location);
         store.Open(OpenFlags.ReadOnly);
         var signingCert = store.Certificates.Find(X509FindType.FindByThumbprint, thumbprint, false);
         if (signingCert.Count == 0)
-            throw new FileNotFoundException($"Certificate with thumbprint: '{thumbprint}' not found in current user cert store.");
+            throw new FileNotFoundException($"Certificate with thumbprint: '{thumbprint}' not found in {locationText} cert store.");
 
         var certificate = signingCert[0];
 
@@ -114,7 +121,7 @@ private static X509Certificate2[] GetCertificatesFromStore(string thumbprint,
 
         // include the whole chain
         var certificates = chain
-            .ChainElements.Cast<X509ChainElement>()
+            .ChainElements
             .Select(c => c.Certificate)
             .OrderByDescending(c => c.HasPrivateKey)
             .ToArray();
diff --git a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.csproj b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.csproj
index 524cdd5..a870dfb 100644
--- a/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.csproj
+++ b/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile/Frends.HTTP.DownloadFile.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>net6.0</TargetFrameworks>
-    <Version>1.3.0</Version>
+    <Version>1.4.0</Version>
     <Authors>Frends</Authors>
 	<Copyright>Frends</Copyright>
 	<Company>Frends</Company>
diff --git a/Frends.HTTP.Request/CHANGELOG.md b/Frends.HTTP.Request/CHANGELOG.md
index 6b27b00..e9a5705 100644
--- a/Frends.HTTP.Request/CHANGELOG.md
+++ b/Frends.HTTP.Request/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## [1.6.0] - 2025-11-18
+### Added
+- Added CertificateStoreLocation option to allow selection between CurrentUser and LocalMachine certificate stores when using certificate authentication.
+
 ## [1.5.0] - 2025-10-03
 ### Changed
 - Changed default return format from String to JToken
diff --git a/Frends.HTTP.Request/Frends.HTTP.Request/Definitions/CertificateStoreLocation.cs b/Frends.HTTP.Request/Frends.HTTP.Request/Definitions/CertificateStoreLocation.cs
new file mode 100644
index 0000000..7cbf8cb
--- /dev/null
+++ b/Frends.HTTP.Request/Frends.HTTP.Request/Definitions/CertificateStoreLocation.cs
@@ -0,0 +1,16 @@
+namespace Frends.HTTP.Request.Definitions;
+
+/// <summary>
+/// Certificate store location.
+/// </summary>
+public enum CertificateStoreLocation
+{
+    /// <summary>
+    /// The X.509 certificate store assigned to the current user.
+    /// </summary>
+    CurrentUser,
+    /// <summary>
+    /// The X.509 certificate store assigned to the local machine.
+    /// </summary>
+    LocalMachine
+}
diff --git a/Frends.HTTP.Request/Frends.HTTP.Request/Definitions/Options.cs b/Frends.HTTP.Request/Frends.HTTP.Request/Definitions/Options.cs
index 27d1ccd..73f27d4 100644
--- a/Frends.HTTP.Request/Frends.HTTP.Request/Definitions/Options.cs
+++ b/Frends.HTTP.Request/Frends.HTTP.Request/Definitions/Options.cs
@@ -80,6 +80,15 @@ public class Options
     [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
     public string CertificateThumbprint { get; set; }
 
+    /// <summary>
+    /// Applicable only when Certificate Source is "CertificateStore".
+    /// Store location for the certificate.
+    /// </summary>
+    /// <example>CurrentUser</example>
+    [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
+    [DefaultValue(CertificateStoreLocation.CurrentUser)]
+    public CertificateStoreLocation CertificateStoreLocation { get; set; }
+
     /// <summary>
     /// Should the entire certificate chain be loaded from the certificate store and included in the request. Only valid when using Certificate Store as the Certificate Source 
     /// </summary>
diff --git a/Frends.HTTP.Request/Frends.HTTP.Request/Extensions.cs b/Frends.HTTP.Request/Frends.HTTP.Request/Extensions.cs
index 5c41542..ba4efdf 100644
--- a/Frends.HTTP.Request/Frends.HTTP.Request/Extensions.cs
+++ b/Frends.HTTP.Request/Frends.HTTP.Request/Extensions.cs
@@ -61,7 +61,7 @@ private static X509Certificate[] GetCertificates(Options options)
         {
             case CertificateSource.CertificateStore:
                 var thumbprint = options.CertificateThumbprint;
-                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate);
+                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate, options.CertificateStoreLocation);
                 break;
             case CertificateSource.File:
                 certificates = GetCertificatesFromFile(options.ClientCertificateFilePath, options.ClientCertificateKeyPhrase);
@@ -105,17 +105,24 @@ private static X509Certificate2[] GetCertificatesFromFile(string clientCertifica
     }
 
     private static X509Certificate2[] GetCertificatesFromStore(string thumbprint,
-        bool loadEntireChain)
+        bool loadEntireChain, CertificateStoreLocation storeLocation)
     {
         thumbprint = Regex.Replace(thumbprint, @"[^\da-zA-z]", string.Empty).ToUpper();
-        using (var store = new X509Store(StoreName.My, StoreLocation.CurrentUser))
+        var location = storeLocation == CertificateStoreLocation.CurrentUser 
+            ? StoreLocation.CurrentUser 
+            : StoreLocation.LocalMachine;
+        var locationText = storeLocation == CertificateStoreLocation.CurrentUser 
+            ? "current user" 
+            : "local machine";
+        
+        using (var store = new X509Store(StoreName.My, location))
         {
             store.Open(OpenFlags.ReadOnly);
             var signingCert = store.Certificates.Find(X509FindType.FindByThumbprint, thumbprint, false);
             if (signingCert.Count == 0)
             {
                 throw new FileNotFoundException(
-                    $"Certificate with thumbprint: '{thumbprint}' not found in current user cert store.");
+                    $"Certificate with thumbprint: '{thumbprint}' not found in {locationText} cert store.");
             }
 
             var certificate = signingCert[0];
diff --git a/Frends.HTTP.Request/Frends.HTTP.Request/Frends.HTTP.Request.csproj b/Frends.HTTP.Request/Frends.HTTP.Request/Frends.HTTP.Request.csproj
index 382e8e1..3eb843e 100644
--- a/Frends.HTTP.Request/Frends.HTTP.Request/Frends.HTTP.Request.csproj
+++ b/Frends.HTTP.Request/Frends.HTTP.Request/Frends.HTTP.Request.csproj
@@ -2,7 +2,7 @@
 
 	<PropertyGroup>
 		<TargetFrameworks>net6.0</TargetFrameworks>
-		<Version>1.5.0</Version>
+		<Version>1.6.0</Version>
 		<Authors>Frends</Authors>
 		<Copyright>Frends</Copyright>
 		<Company>Frends</Company>
diff --git a/Frends.HTTP.RequestBytes/CHANGELOG.md b/Frends.HTTP.RequestBytes/CHANGELOG.md
index d03e15b..e972dc9 100644
--- a/Frends.HTTP.RequestBytes/CHANGELOG.md
+++ b/Frends.HTTP.RequestBytes/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## [1.4.0] - 2025-11-18
+### Added
+- Added CertificateStoreLocation option to allow selection between CurrentUser and LocalMachine certificate stores when using certificate authentication.
+
 ## [1.3.0] - 2025-10-10
 ### Changed
 - Changed the return type of RequestBytes from Task<object> to Task<Result>
diff --git a/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Definitions/CertificateStoreLocation.cs b/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Definitions/CertificateStoreLocation.cs
new file mode 100644
index 0000000..cdeadc7
--- /dev/null
+++ b/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Definitions/CertificateStoreLocation.cs
@@ -0,0 +1,16 @@
+namespace Frends.HTTP.RequestBytes.Definitions;
+
+/// <summary>
+/// Certificate store location.
+/// </summary>
+public enum CertificateStoreLocation
+{
+    /// <summary>
+    /// The X.509 certificate store assigned to the current user.
+    /// </summary>
+    CurrentUser,
+    /// <summary>
+    /// The X.509 certificate store assigned to the local machine.
+    /// </summary>
+    LocalMachine
+}
diff --git a/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Definitions/Options.cs b/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Definitions/Options.cs
index c1df7ed..eb3953f 100644
--- a/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Definitions/Options.cs
+++ b/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Definitions/Options.cs
@@ -80,6 +80,15 @@ public class Options
     [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
     public string CertificateThumbprint { get; set; }
 
+    /// <summary>
+    /// Applicable only when Certificate Source is "CertificateStore".
+    /// Store location for the certificate.
+    /// </summary>
+    /// <example>CurrentUser</example>
+    [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
+    [DefaultValue(CertificateStoreLocation.CurrentUser)]
+    public CertificateStoreLocation CertificateStoreLocation { get; set; }
+
     /// <summary>
     /// Should the entire certificate chain be loaded from the certificate store and included in the request. Only valid when using Certificate Store as the Certificate Source 
     /// </summary>
diff --git a/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Extensions.cs b/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Extensions.cs
index d73fc0b..48b4807 100644
--- a/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Extensions.cs
+++ b/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Extensions.cs
@@ -61,7 +61,7 @@ private static X509Certificate[] GetCertificates(Options options)
         {
             case CertificateSource.CertificateStore:
                 var thumbprint = options.CertificateThumbprint;
-                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate);
+                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate, options.CertificateStoreLocation);
                 break;
             case CertificateSource.File:
                 certificates = GetCertificatesFromFile(options.ClientCertificateFilePath, options.ClientCertificateKeyPhrase);
@@ -105,17 +105,24 @@ private static X509Certificate2[] GetCertificatesFromFile(string clientCertifica
     }
 
     private static X509Certificate2[] GetCertificatesFromStore(string thumbprint,
-        bool loadEntireChain)
+        bool loadEntireChain, CertificateStoreLocation storeLocation)
     {
         thumbprint = Regex.Replace(thumbprint, @"[^\da-zA-z]", string.Empty).ToUpper();
-        using (var store = new X509Store(StoreName.My, StoreLocation.CurrentUser))
+        var location = storeLocation == CertificateStoreLocation.CurrentUser 
+            ? StoreLocation.CurrentUser 
+            : StoreLocation.LocalMachine;
+        var locationText = storeLocation == CertificateStoreLocation.CurrentUser 
+            ? "current user" 
+            : "local machine";
+        
+        using (var store = new X509Store(StoreName.My, location))
         {
             store.Open(OpenFlags.ReadOnly);
             var signingCert = store.Certificates.Find(X509FindType.FindByThumbprint, thumbprint, false);
             if (signingCert.Count == 0)
             {
                 throw new FileNotFoundException(
-                    $"Certificate with thumbprint: '{thumbprint}' not found in current user cert store.");
+                    $"Certificate with thumbprint: '{thumbprint}' not found in {locationText} cert store.");
             }
 
             var certificate = signingCert[0];
diff --git a/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes.csproj b/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes.csproj
index 8e84d7a..4d7743f 100644
--- a/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes.csproj
+++ b/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes/Frends.HTTP.RequestBytes.csproj
@@ -2,7 +2,7 @@
 
 	<PropertyGroup>
 		<TargetFrameworks>net6.0</TargetFrameworks>
-		<Version>1.3.0</Version>
+		<Version>1.4.0</Version>
 		<Authors>Frends</Authors>
 		<Copyright>Frends</Copyright>
 		<Company>Frends</Company>
diff --git a/Frends.HTTP.SendAndReceiveBytes/CHANGELOG.md b/Frends.HTTP.SendAndReceiveBytes/CHANGELOG.md
index 3f1633e..a3ea9bc 100644
--- a/Frends.HTTP.SendAndReceiveBytes/CHANGELOG.md
+++ b/Frends.HTTP.SendAndReceiveBytes/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## [1.4.0] - 2025-11-18
+### Added
+- Added CertificateStoreLocation option to allow selection between CurrentUser and LocalMachine certificate stores when using certificate authentication.
+
 ## [1.3.0] - 2025-10-10
 ### Changed
 - Changed the return type of SendAndReceiveBytes from Task<object> to Task<Result>
diff --git a/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Definitions/CertificateStoreLocation.cs b/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Definitions/CertificateStoreLocation.cs
new file mode 100644
index 0000000..e225084
--- /dev/null
+++ b/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Definitions/CertificateStoreLocation.cs
@@ -0,0 +1,16 @@
+namespace Frends.HTTP.SendAndReceiveBytes.Definitions;
+
+/// <summary>
+/// Certificate store location.
+/// </summary>
+public enum CertificateStoreLocation
+{
+    /// <summary>
+    /// The X.509 certificate store assigned to the current user.
+    /// </summary>
+    CurrentUser,
+    /// <summary>
+    /// The X.509 certificate store assigned to the local machine.
+    /// </summary>
+    LocalMachine
+}
diff --git a/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Definitions/Options.cs b/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Definitions/Options.cs
index 0a3e108..22e4c4b 100644
--- a/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Definitions/Options.cs
+++ b/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Definitions/Options.cs
@@ -83,6 +83,15 @@ public class Options
     [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
     public string CertificateThumbprint { get; set; }
 
+    /// <summary>
+    /// Applicable only when Certificate Source is "CertificateStore".
+    /// Store location for the certificate.
+    /// </summary>
+    /// <example>CurrentUser</example>
+    [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
+    [DefaultValue(CertificateStoreLocation.CurrentUser)]
+    public CertificateStoreLocation CertificateStoreLocation { get; set; }
+
     /// <summary>
     /// Should the entire certificate chain be loaded from the certificate store and included in the request. Only valid when using Certificate Store as the Certificate Source 
     /// </summary>
diff --git a/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Extensions.cs b/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Extensions.cs
index 308f16d..8340723 100644
--- a/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Extensions.cs
+++ b/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Extensions.cs
@@ -59,7 +59,7 @@ private static X509Certificate[] GetCertificates(Options options)
         {
             case CertificateSource.CertificateStore:
                 var thumbprint = options.CertificateThumbprint;
-                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate);
+                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate, options.CertificateStoreLocation);
                 break;
             case CertificateSource.File:
                 certificates = GetCertificatesFromFile(options.ClientCertificateFilePath, options.ClientCertificateKeyPhrase);
@@ -103,17 +103,24 @@ private static X509Certificate2[] GetCertificatesFromFile(string clientCertifica
     }
 
     private static X509Certificate2[] GetCertificatesFromStore(string thumbprint,
-        bool loadEntireChain)
+        bool loadEntireChain, CertificateStoreLocation storeLocation)
     {
         thumbprint = Regex.Replace(thumbprint, @"[^\da-zA-z]", string.Empty).ToUpper();
-        using (var store = new X509Store(StoreName.My, StoreLocation.CurrentUser))
+        var location = storeLocation == CertificateStoreLocation.CurrentUser 
+            ? StoreLocation.CurrentUser 
+            : StoreLocation.LocalMachine;
+        var locationText = storeLocation == CertificateStoreLocation.CurrentUser 
+            ? "current user" 
+            : "local machine";
+        
+        using (var store = new X509Store(StoreName.My, location))
         {
             store.Open(OpenFlags.ReadOnly);
             var signingCert = store.Certificates.Find(X509FindType.FindByThumbprint, thumbprint, false);
             if (signingCert.Count == 0)
             {
                 throw new FileNotFoundException(
-                    $"Certificate with thumbprint: '{thumbprint}' not found in current user cert store.");
+                    $"Certificate with thumbprint: '{thumbprint}' not found in {locationText} cert store.");
             }
 
             var certificate = signingCert[0];
diff --git a/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes.csproj b/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes.csproj
index 21b2249..1d53546 100644
--- a/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes.csproj
+++ b/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes/Frends.HTTP.SendAndReceiveBytes.csproj
@@ -2,7 +2,7 @@
 
 	<PropertyGroup>
 		<TargetFrameworks>net6.0</TargetFrameworks>
-		<Version>1.3.0</Version>
+		<Version>1.4.0</Version>
 		<Authors>Frends</Authors>
 		<Copyright>Frends</Copyright>
 		<Company>Frends</Company>
diff --git a/Frends.HTTP.SendBytes/CHANGELOG.md b/Frends.HTTP.SendBytes/CHANGELOG.md
index f633c78..fac8fe5 100644
--- a/Frends.HTTP.SendBytes/CHANGELOG.md
+++ b/Frends.HTTP.SendBytes/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## [1.5.0] - 2025-11-18
+### Added
+- Added CertificateStoreLocation option to allow selection between CurrentUser and LocalMachine certificate stores when using certificate authentication.
+
 ## [1.4.0] - 2025-10-10
 ### Changed
 - Changed the return type of SendBytes from Task<object> to Task<Result>
diff --git a/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Definitions/CertificateStoreLocation.cs b/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Definitions/CertificateStoreLocation.cs
new file mode 100644
index 0000000..56069bd
--- /dev/null
+++ b/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Definitions/CertificateStoreLocation.cs
@@ -0,0 +1,16 @@
+namespace Frends.HTTP.SendBytes.Definitions;
+
+/// <summary>
+/// Certificate store location.
+/// </summary>
+public enum CertificateStoreLocation
+{
+    /// <summary>
+    /// The X.509 certificate store assigned to the current user.
+    /// </summary>
+    CurrentUser,
+    /// <summary>
+    /// The X.509 certificate store assigned to the local machine.
+    /// </summary>
+    LocalMachine
+}
diff --git a/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Definitions/Options.cs b/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Definitions/Options.cs
index 42ca4ab..2ff9451 100644
--- a/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Definitions/Options.cs
+++ b/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Definitions/Options.cs
@@ -80,6 +80,15 @@ public class Options
     [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
     public string CertificateThumbprint { get; set; }
 
+    /// <summary>
+    /// Applicable only when Certificate Source is "CertificateStore".
+    /// Store location for the certificate.
+    /// </summary>
+    /// <example>CurrentUser</example>
+    [UIHint(nameof(Authentication), "", Authentication.ClientCertificate)]
+    [DefaultValue(CertificateStoreLocation.CurrentUser)]
+    public CertificateStoreLocation CertificateStoreLocation { get; set; }
+
     /// <summary>
     /// Should the entire certificate chain be loaded from the certificate store and included in the request. Only valid when using Certificate Store as the Certificate Source 
     /// </summary>
diff --git a/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Extensions.cs b/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Extensions.cs
index 2602daa..3adee62 100644
--- a/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Extensions.cs
+++ b/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Extensions.cs
@@ -59,7 +59,7 @@ private static X509Certificate[] GetCertificates(Options options)
         {
             case CertificateSource.CertificateStore:
                 var thumbprint = options.CertificateThumbprint;
-                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate);
+                certificates = GetCertificatesFromStore(thumbprint, options.LoadEntireChainForCertificate, options.CertificateStoreLocation);
                 break;
             case CertificateSource.File:
                 certificates = GetCertificatesFromFile(options.ClientCertificateFilePath, options.ClientCertificateKeyPhrase);
@@ -103,17 +103,24 @@ private static X509Certificate2[] GetCertificatesFromFile(string clientCertifica
     }
 
     private static X509Certificate2[] GetCertificatesFromStore(string thumbprint,
-        bool loadEntireChain)
+        bool loadEntireChain, CertificateStoreLocation storeLocation)
     {
         thumbprint = Regex.Replace(thumbprint, @"[^\da-zA-z]", string.Empty).ToUpper();
-        using (var store = new X509Store(StoreName.My, StoreLocation.CurrentUser))
+        var location = storeLocation == CertificateStoreLocation.CurrentUser 
+            ? StoreLocation.CurrentUser 
+            : StoreLocation.LocalMachine;
+        var locationText = storeLocation == CertificateStoreLocation.CurrentUser 
+            ? "current user" 
+            : "local machine";
+        
+        using (var store = new X509Store(StoreName.My, location))
         {
             store.Open(OpenFlags.ReadOnly);
             var signingCert = store.Certificates.Find(X509FindType.FindByThumbprint, thumbprint, false);
             if (signingCert.Count == 0)
             {
                 throw new FileNotFoundException(
-                    $"Certificate with thumbprint: '{thumbprint}' not found in current user cert store.");
+                    $"Certificate with thumbprint: '{thumbprint}' not found in {locationText} cert store.");
             }
 
             var certificate = signingCert[0];
diff --git a/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes.csproj b/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes.csproj
index e0f3a22..781c5c0 100644
--- a/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes.csproj
+++ b/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes/Frends.HTTP.SendBytes.csproj
@@ -2,7 +2,7 @@
 
 	<PropertyGroup>
 		<TargetFrameworks>net6.0</TargetFrameworks>
-		<Version>1.4.0</Version>
+		<Version>1.5.0</Version>
 		<Authors>Frends</Authors>
 		<Copyright>Frends</Copyright>
 		<Company>Frends</Company>