pytorch - 💡(How to fix) Fix Windows Application Control (WDAC) blocks loading unsigned torch DLL [3 comments, 2 participants]

When we import torch in our application that embeds Python, we sometimes see the following error: [WinError 4551] An Application Control policy has blocked this file. Error loading "<Redacted>\Python311\site-packages\torch\lib\torch.dll" or one of its dependencies.

TL;DR

Signing the torch.dll file or its dependencies may resolve the Windows Application Control policy blockage.

Guidance

• Investigate the specific dependencies of torch.dll to identify which ones lack a signature, as the error message indicates it could be one of its dependencies causing the issue.
• Consider reaching out to the PyTorch team or maintainers to request signed versions of the DLLs, as suggested in the issue.
• If possible, test the application in an environment with less restrictive Application Control policies to verify if the issue is indeed related to the policy blockage.
• Review Windows documentation on Application Control policies to understand how to configure or exempt specific DLLs from these policies as a potential workaround.

Notes

The solution depends on the ability to either obtain signed versions of the DLLs or configure the Windows environment to trust unsigned DLLs, which may have security implications.

Recommendation

Apply a workaround by configuring Windows to exempt the specific torch.dll and its dependencies from Application Control policies, as obtaining signed versions may not be immediately feasible.