NOTE: Please click the "Me too" link to the right of this post if you experiencing this issue so that Microsoft and Avast take notice of it. Thanks.
Short Story: Avast 2014 appears to interfere with the app shortcut cleanup process that occurs during the 8 -> 8.1 update. Also, Windows 8.1 really needs an easy/elegant way to remove dead Modern app shortcuts as you can with dead desktop app shortcuts
I updated from Windows 8 Pro x64 with Media Center on my 2 machines (Ivy Bridge Core i3 & i7) via the Windows Store and have had multiple broken/dead app shortcuts in All Apps on both machines as seen in the red rectangle below (direct image link):
When I attempt to launch any of the apps by clicking the shortcuts, I get the following message (the "Microsoft.Camera" part is specific to 1 of the shortcuts I tried) (direct image link):
Clicking the Go to the Store link only produces this message in the Windows Store app (direct image link):
Returning to All Apps and right clicking any of the dead shortcuts to remove it exposes no such option. There's no way to uninstall the app (it's probably gone already gone anyway) and also no way to remove the dead shortcut. As you can see below. the only options are Pin to Start and Customize (direct image link):
Does anyone know how to remove the dead shortcuts? I've tried going to C:\Program Files\WindowsApps\, but access to that is denied and I can't find any way to give myself permissions for it. The offending shortcuts aren't listed in Control Panel -> Programs and Features, C:\Users\<username>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs, or C:\ProgramData\Microsoft\Windows\Start Menu either. Microsoft's own Apps Diagnostic utility doesn't fix it, and neither does syncing app licenses within the Windows Store app.
Help? Any ideas? TIA