diff --git a/R/file_checks.R b/R/file_checks.R
index a645042..937287e 100644
--- a/R/file_checks.R
+++ b/R/file_checks.R
@@ -10,7 +10,7 @@
 #' @export
 check_dir_writable <- function(dir) {
   log_trace("Checking if directory is writable: ", dir)
-  if (tolower(Sys.info()["sysname"]) == "windows") {
+  if (tolower(Sys.info()[["sysname"]]) == "windows") {
     log_warn("Function check_dir_writable is not tested on Windows.")
     warning("check_dir_writable may return incorrect results on Windows.")
   }
diff --git a/tests/testthat/test-check_dir_writable.R b/tests/testthat/test-check_dir_writable.R
index fc91e14..198335b 100644
--- a/tests/testthat/test-check_dir_writable.R
+++ b/tests/testthat/test-check_dir_writable.R
@@ -36,4 +36,3 @@ test_that("check_dir_writable emits warning on windows.", {
     regexp = "^check_dir_writable may return incorrect results on Windows.$"
   )
 })
-