Medium
Operating Systems
✓ Solution Verified by Community (0+ upvotes)
How to fix error 0x800705b9 in Windows 11
ERROR_INSTALL_FAILURE: Installation failure.
Fix based on community reports and expert analysis. Last verified: 2026-08-12
· How we verify fixes
| Error Code | 0x800705b9 |
|---|---|
| Affected System | Windows 11 (Microsoft) |
| Difficulty | Medium |
| Estimated Time | 45 min |
| Requires Admin Rights | ⚠️ Yes |
Solution Steps
- 1 Press Windows key + R, type 'services.msc', and press Enter. In the Services window, find 'Windows Installer'. Right-click it and select 'Start' if it's not running, or 'Restart' if it is. This ensures the service is active, as it must be running for installations to work.
- 2 Press Windows key + I to open Settings. Go to Apps → Installed apps. Find the problematic program, click the three dots, and select 'Uninstall'. Then reinstall it from the original source. This clears any corrupted installation files.
- 3 Press Windows key + X and select 'Terminal (Admin)'. Type 'msiexec /unregister' and press Enter, then type 'msiexec /regserver' and press Enter. This re-registers the Windows Installer service, which can fix registration issues that cause failures.
- 4 Temporarily disable your antivirus software (if you have third-party antivirus) and try the installation again. Sometimes antivirus blocks installer operations. Remember to re-enable it after.
- 5 If the error persists, use the Windows Installer CleanUp Utility (download from Microsoft) to remove leftover installer data, then reinstall the software.
Alternative Solutions
Method 2 (1 upvotes)
- Reboot the system and retry the update.
- Check free space on the system drive and ensure at least 10-15 GB is free.
- Temporarily disable third-party antivirus or firewall and retry the update.
- Run the Windows Update troubleshooter: Settings -> System -> Troubleshoot -> Other troubleshooters -> Windows Update, apply any fixes, and restart.
- Open Command Prompt and run: sfc /verifyonly
- If the issue started after a preview update, uninstall KB5101684 from Settings -> Windows Update -> Update History -> Uninstall Updates.
- Disable 'Get the latest updates as soon as they are released' in Windows Update settings.
- If the problem continues, use the built-in Windows Update repair option: Settings -> System -> Recovery -> Reinstall Now under 'Fix problems with Windows Updates'.
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