ImportError: DLL load failed while importing snowflake.connector (snowflake-connector-python)

TL;DR: The connector's native extension cannot find a DLL it needs on Windows. Install the Microsoft Visual C++ Redistributable, then make sure pyarrow and snowflake-connector-python versions are compatible (upgrade both).

ImportError: DLL load failed while importing snowflake.connector: The specified module could not be found.

Fix it

1. Install the latest Microsoft Visual C++ Redistributable (x64) and reboot. Expected: the missing system DLLs exist.
2. Upgrade both packages: pip install -U snowflake-connector-python pyarrow. Expected: compatible pair.
3. Verify: python -c "import snowflake.connector; print(snowflake.connector.version)". Expected: a version, no traceback.
4. If it persists, check for multiple pyarrow installs or a stale .pyd in site-packages and clean-reinstall.

When this applies

• import snowflake.connector raises DLL load failed on Windows.

When it doesn't

• The import works but connect() fails: network/auth problem, different fix.
• You are on Linux/Mac: DLL errors do not apply; check the actual message.

Compatibility

• snowflake-connector-python 3.x; pyarrow compatible version; Windows 10/11.

Why it happens

The connector ships compiled extensions linked against the VC++ runtime and pyarrow's DLLs. A missing runtime or a pyarrow version whose DLLs moved breaks the load.

Edge cases

• Conda envs sometimes mix pip and conda pyarrow builds; use one installer.
• 32-bit Python on 64-bit Windows causes its own DLL hell; use 64-bit Python.

Reported in a troubleshooting doc (doc:Alteryx community Snowflake connector openSSL thread): ImportError: DLL load failed while importing _openssl via import snowflake.connector. The verified fix: Asked on Stack Overflow by Windows developers whose import snowflake.connector failed with DLL load failed. The verified answer: a missing or mismatched native dependency (pyarrow/OpenSSL via the Visual C++ runtime), so install the VC++ redistributable and align pyarrow/snowflake-connector versions. Source: the linked Stack Overflow thread. Source: https://community.alteryx.com/t5/Dev-Space/Issue-creating-Virtual-Environment-with-Snowflake-Connector/m-p/680085 Thread ref: doc:Alteryx community Snowflake connector openSSL thread