0x80073cf9 — App install/update failed (Microsoft Store) – How to Fix

The error code 0x80073cf9 typically shows up when installing or updating apps from the Microsoft Store. It signals that Windows cannot create or access the folders and caches needed to complete the operation. While it may look like a major system failure, the root cause is usually a missing or corrupted folder, insufficient permissions, or lack of space on the system drive.

Have a different error code? Figure out how to fix it with our free Windows error code decoder.

Causes

The most common triggers for this error include:

• Missing AUInstallAgent folder in the Windows directory
• Corrupted Microsoft Store cache
• App install location set to a secondary drive rather than the system drive
• Insufficient free space on the system partition
• Permission problems preventing Windows from creating or modifying required files

Fixes

Create or restore the AUInstallAgent folder

One of the most common causes of 0x80073cf9 is a missing or inaccessible AUInstallAgent folder.

1. Navigate to C:\Windows\.
2. Look for a folder named AUInstallAgent.
3. If it doesn’t exist, create a new folder with that name.
4. Right-click the folder, select Properties → Security tab, and ensure both SYSTEM and Administrators have Full Control permissions.

This step restores the default environment Microsoft Store expects.

Reset the Microsoft Store cache

A corrupted cache can block app updates. Reset it using:

wsreset

This command clears the cache and restarts the Microsoft Store with default settings. You can also reset via Settings → Apps → Microsoft Store → Advanced options → Reset.

Move install location back to system drive

If you’ve set apps to install on another drive, some updates may fail. To fix:

1. Open Settings → System → Storage → Advanced storage settings → Where new content is saved.
2. Set New apps will save to: the system drive (usually C:).
   Retry the installation after this change.

Ensure sufficient free space

Microsoft Store updates often require significant temporary space. Check your system partition for free space:

• Open File Explorer, right-click the C: drive, and choose Properties.
• Free up space by running Storage Sense in Settings or using Disk Cleanup.
  Having at least 10–15 GB free is recommended for large updates.

Additional checks

• Windows Update services: The Store relies on Windows Update services. Restart them using services.msc or via Command Prompt with net stop wuauserv and net start wuauserv.
• Check for pending updates: Install any outstanding Windows Updates before retrying the Store operation.
• Re-register Microsoft Store: Open PowerShell (Admin) and run: Get-AppxPackage -allusers Microsoft.WindowsStore | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}

This reinstalls the Store app itself.

Conclusion

The 0x80073cf9 error in Microsoft Store usually traces back to missing folders, cache corruption, or storage problems. Recreating the AUInstallAgent folder, resetting the cache, ensuring apps install to the system drive, and freeing disk space usually solve the issue. For stubborn cases, re-registering the Store app or ensuring all Windows Updates are applied provides a complete fix.

Have a different error code? Figure out how to fix it with our free Windows error code decoder.