diff --git a/python/scripts/prepare_envs.ps1 b/python/scripts/prepare_envs.ps1
index 3fa879dc7..7205bfffa 100644
--- a/python/scripts/prepare_envs.ps1
+++ b/python/scripts/prepare_envs.ps1
@@ -62,6 +62,8 @@ if (-not (Test-Path ".venv")) {
 }
 Highlight-Command "uv sync --group dev"
 uv sync --group dev
+# https://stackoverflow.com/questions/74267313/how-to-use-tzdata-file-with-pyarrow-compute-assume-timezone/74292266
+uv run -s "python -c 'import pyarrow.util; pyarrow.util.download_tzdata_on_windows()'"
 Write-Success "Main environment setup complete."
 
 Write-Highlight "=========================================="
diff --git a/python/valuecell/agents/research_agent/sources.py b/python/valuecell/agents/research_agent/sources.py
index 50f4869f6..51861dbf7 100644
--- a/python/valuecell/agents/research_agent/sources.py
+++ b/python/valuecell/agents/research_agent/sources.py
@@ -71,7 +71,7 @@ async def _write_and_ingest(
             period_of_report=period_of_report,
             filing_date=filing_date,
         )
-        async with aiofiles.open(path, "w") as file:
+        async with aiofiles.open(path, "w", encoding="utf-8") as file:
             await file.write(content)
 
         result = SECFilingResult(file_name, path, metadata)