How to Fix FileCoAuth.exe – Application Error on Windows

Some Windows users encounter the “FileCoAuth.exe – Application Error” message while opening, syncing, or collaborating on Microsoft Office files. In many cases, the error appears randomly when using apps such as Microsoft Word, Microsoft Excel, Microsoft PowerPoint, or cloud-based services like Microsoft OneDrive and Microsoft SharePoint.

FileCoAuth.exe is a legitimate Microsoft Office component responsible for file co-authoring and synchronization features. It enables multiple users to collaborate on Office documents simultaneously. However, if the process becomes corrupted or conflicts with Office services, Windows may display application errors, crashes, or synchronization failures.

This issue is commonly caused by corrupted Office files, damaged OneDrive cache, outdated Office builds, synchronization conflicts, antivirus interference, or corrupted user profiles.

In this guide, we’ll walk you through several effective methods to fix the FileCoAuth.exe – Application Error issue on Windows 11.

How to Fix FileCoAuth.exe – Application Error on Windows

Before trying advanced troubleshooting methods, save all Office documents and close Microsoft Office applications completely. Follow the methods below in order for the best results.

1. Restart Your PC

Temporary Office or synchronization service glitches may trigger FileCoAuth.exe errors.

1. Save your work.
2. Restart your Windows PC.
3. Open the Office application again.
4. Check whether the error still appears.

Restarting refreshes Office background services and sync components.

2. Update Microsoft Office

Outdated Office builds may contain synchronization bugs.

1. Open any Office application.
2. Navigate to: File > Account
3. Click: Update Options > Update Now
4. Install all available updates.
5. Restart your PC afterward.

Updated Office builds often fix co-authoring and sync-related problems.

3. Repair Microsoft Office

Corrupted Office installation files commonly cause FileCoAuth.exe errors.

1. Open: Settings > Apps > Installed apps
2. Locate: Microsoft 365 or Office installation.
3. Click: Modify
4. Choose:
   • Quick Repair
   • Online Repair (if necessary)
5. Restart your PC afterward.

This repairs damaged Office components automatically.

4. Reset OneDrive

Synchronization conflicts with Microsoft OneDrive may trigger FileCoAuth.exe crashes.

1. Press: Windows + R
2. Enter:

%localappdata%\Microsoft\OneDrive\OneDrive.exe /reset

3. Press Enter.
4. Restart OneDrive afterward.

This refreshes OneDrive synchronization settings and cache.

5. Clear Office Document Cache

Corrupted Office cache files may interfere with co-authoring services.

1. Close all Office applications.
2. Press: Windows + R
3. Enter:

%localappdata%\Microsoft\Office

4. Locate Office cache-related folders.
5. Delete temporary cache files carefully.
6. Restart Office applications.

This rebuilds Office synchronization cache data.

6. Disable Office Sync Features Temporarily

Cloud synchronization conflicts may trigger the error repeatedly.

1. Open:
   Microsoft OneDrive settings.
2. Disable: Use Office applications to sync Office files that I open
3. Restart your PC afterward.

This may reduce synchronization conflicts temporarily.

7. Run System File Checker

Corrupted Windows system files may affect Office components.

1. Open Command Prompt as Administrator.
2. Run:

sfc /scannow

3. Wait for the scan to finish.
4. Restart your PC afterward.

This repairs damaged Windows system components automatically.

8. Disable Antivirus Temporarily

Some antivirus software may interfere with Office synchronization processes.

1. Temporarily disable third-party antivirus software.
2. Retry opening or syncing Office documents.
3. Re-enable antivirus protection afterward.

Do not leave security protection disabled permanently.

9. Create a New Windows User Profile

Corrupted user profiles may trigger FileCoAuth.exe crashes.

1. Open: Settings > Accounts > Other users
2. Create a new user account.
3. Sign into the new account.
4. Test Office applications again.

If the issue disappears, the original user profile may be corrupted.

10. Reinstall Microsoft Office

If the issue persists, perform a clean Office reinstall.

1. Uninstall Microsoft Office completely.
2. Restart your PC.
3. Reinstall Office from:

Microsoft 365 Portal

Fresh installations often resolve corrupted co-authoring services and synchronization components.

Additional Tips

To reduce future FileCoAuth.exe errors:

• Keep Office updated regularly
• Maintain stable internet connectivity
• Avoid force-closing Office apps during syncing
• Keep OneDrive updated
• Use official Microsoft Office installations only

These practices improve Office collaboration stability significantly.

Conclusion

The FileCoAuth.exe – Application Error issue is usually caused by corrupted Office files, damaged synchronization cache, OneDrive conflicts, outdated Office builds, or user profile problems. Fortunately, most users can resolve the issue using methods such as repairing Office, resetting OneDrive, clearing Office cache files, or reinstalling Microsoft Office.

By following the solutions outlined above, you should be able to restore normal Office co-authoring and synchronization functionality on Windows 11.