sfc /scannow DISM /Online /Cleanup-Image /RestoreHealth Some aggressive antivirus software quarantines legitimate DLLs. If disabling AV fixes the issue, add an exception for the app folder. ✅ Fix 8: Check for missing dependency-of-dependency Use Dependency Walker to see if DLL A is present but DLL B (which A needs) is missing. You may need to install an additional redistributable or library pack. Real-World Example Scenario: A user installs a Python application packaged with PyInstaller. When running the .exe , they see: Failed to load python3.dll – Win32 error 126