Troubleshooting: "WinDivert driver cannot be installed. You must restart your computer."
If you are seeing the error message "WinDivert driver cannot be installed you must restart your computer to complete the installation" (or a variation regarding the WinDivert driver), it typically indicates a conflict with a previous driver state or a pending system operation.
This error is commonly associated with networking tools, ad-blockers (like Portmaster or certain GitHub projects), and packet sniffing applications that rely on the WinDivert library to capture and filter network traffic.
Here is a breakdown of why this happens and how to resolve it.
Run System File Checker:
- Open Command Prompt as Administrator.
- Run:
sfc /scannow
- Wait for completion (may take 15+ minutes).
- Then run:
DISM /Online /Cleanup-Image /RestoreHealth
- Restart and try again.
Fix 4: Disable Driver Signature Enforcement (Temporary)
For 64-bit Windows with Secure Boot:
- Go to Settings > Update & Security > Recovery.
- Under Advanced startup, click Restart now.
- After reboot, choose Troubleshoot > Advanced Options > Startup Settings.
- Click Restart, then press 7 or F7 for “Disable driver signature enforcement”.
- Install your WinDivert app while enforcement is off.
- Reboot normally – the driver will remain loaded.
Note: This only works temporarily for installation. You won’t need to do it every time once installed.
Common Misconceptions (Debunked)
- "This error means my computer has a virus." – No. WinDivert is legitimate. Some malware uses similar techniques, but the error itself is a normal Windows security response.
- "Restarting over and over will fix it." – No. Without clearing the pending flag or admin rights, repeated restarts waste time.
- "I should reinstall Windows." – Almost never necessary. Solutions 1-5 resolve 99% of cases.
- "Only old VPNs have this issue." – No. Even modern tools like Cloudflare WARP (in some modes) and Proxifier use WinDivert.