We recently got a call from a customer stating that they could no longer launch Windows 8 Apps from the Metro interface.

The apps all have a white cross (X) in the lower right and nothing happens when you click them.  Some gave random errors, but none would launch. Not even the store or settings Apps.

Also in the Windows error logs were various error's such as: 

*Activation of application winstore_cw5n1h2txyewy!Windows.Store failed with error: This application does not support the contract specified or is not installed. See the Microsoft-Windows-TWinUI/Operational log for additional information.*

We spent approximately 7 hours trying to resolve this, including calls to MS Partner support that were less than helpful in this instance and after much troubleshooting and following endless suggested fixes we finally got a hit.

So heres what you need to do! Note: you may have tried some of these steps already, however please start again from the beginning.

When trying launch Windows Apps from the Metro interface you may find the apps don't launch, they also may have an X displayed in the bottom right hand corner.

Running the Windows App Trouble Shooter may result in the error:

Windows Store Cache May Be Damaged

Running WSReset.exe may give you errors about being unable to clear the Cache

The issue comes down to permission problems with both the Windows registry and the Windows Apps file system.

To repair this issue perform the following:

1. Navigate to C:\Program Files\WindowsApps
2. Right click on the folder, choose properties, (click Continue if permission error is given), click the Advanced button in bottom right.
3. Click the Change link at the top next to Owner and set your user account to be owner of the folder.
4. Apply and OK your way out of the screens.
5. Go back in to the Properties Window and give your account Full Access to the folder and sub folders.
6. Apply and OK your way out again.
7. Open Regedit (START > RUN > regedit > OK)
8. Browse to the registry key at HKEY_CURRENT_USER\Software\Classes\Local Settings\software\microsoft\windows\currentversion\appmodel\repository\packages.
9. Right click on the “packages” key and bring up the “Permissions” tab.
10. Click the “Advanced” button located at the bottom right corner.
11. Check to see the account name that shows up as the “Owner” (this is the first line of text on the “advanced security settings” dialog for the “packages” key). It should say “SYSTEM”.  (For me this showed the built-in local Administrators group)
12. If it is any other account, click on the “Change” button next to it.
13. Type SYSTEM in the “select user” dialog. If “Multiple Names Found” window comes up, select the row for “SYSTEM”.
14. Click OK to the dialogs and close them all.
15. Take ownership of: C:\ProgramData\Microsoft\Windows\AppRepository (There are tutorials all over the place on how to do this if needed.)
16. Delete "PackageRepository.edb". You should also delete the edb.log andedb(numberxxx).log files. (I did NOT delete any XML files because I have so many unrelated ones in that folder).
17. Reboot. 
18. Open Windows PowerShell as Administrator 
19. Copy and paste these 3 commands

powershell -ExecutionPolicy Unrestricted Add-AppxPackage -DisableDevelopmentMode -Register $Env:SystemRoot\camera\AppxManifest.xml 

powershell -ExecutionPolicy Unrestricted Add-AppxPackage -DisableDevelopmentMode -Register $Env:SystemRoot\FileManager\AppxManifest.xml 

powershell -ExecutionPolicy Unrestricted Add-AppxPackage -DisableDevelopmentMode -Register $Env:SystemRoot\ImmersiveControlPanel\AppxManifest.xml

Reboot and all should be well.

You may find now that when you go in to your Apps they come up with a message stating that they need to be repaired.  Click the link in the message to go to the store, a further message will come up stating the app needs to be repaired, click the repair button and it will reinstall the damaged App. 

If this helped you out then please let us know on Twitter. 

Here are some other error messages that you may see on your journey in to resolving this problem:

"Add-AppxPackage : Deployment failed with HRESULT: 0x80073CFE"

"Add-AppxPackage : Deployment failed with HRESULT: 0x80073CFE, The package
repository is corrupted."

"Windows cannot process a deployment operation because the package
repository database encountered an ESENT error"

" windows cannot find 'ms-windows-store:purge caches' "

"Activation of app winstore_cw5n1h2txyewy!Windows.Store failed with error: This app does not support the contract specified or is not installed. See the Microsoft-Windows-TWinUI/Operational log for additional information"

"error 0x8007064A: Cannot register the request because the following error was encountered while initializing the windows.repositoryExtension extension: The
configuration data for this product is corrupt. Contact your support personnel"

"MessageId: ERROR_PACKAGE_REPOSITORY_CORRUPTED"