Upgraded to 1903 - Most Win Apps fail to launch

Subject line describes it well. Nearly every Win app fails to run (some show splash screen which quickly disappears). Edge and Sticky Notes are working... but not much else.

When I launch calculator it fails, leaving this trail in Event Viewer:

"Failed with 0x5 retrieving AppModel Runtime status for package Microsoft.WindowsCalculator_10.1905.28.0_x64__8wekyb3d8bbwe."

and this:
Faulting application name: Calculator.exe, version: 10.1905.28.0, time stamp: 0x5cf593c9
Faulting module name: twinapi.appcore.dll, version: 10.0.18362.1, time stamp: 0x42f071ca
Exception code: 0xc0000409
Fault offset: 0x00000000000a3e0e
Faulting process id: 0x60
Faulting application start time: 0x01d52f88f9c746aa
Faulting application path: C:\Program Files\WindowsApps\Microsoft.WindowsCalculator_10.1905.28.0_x64__8wekyb3d8bbwe\Calculator.exe
Faulting module path: C:\Windows\System32\twinapi.appcore.dll
Report Id: aa8aba9a-b738-4e91-bf65-984f74f070de
Faulting package full name: Microsoft.WindowsCalculator_10.1905.28.0_x64__8wekyb3d8bbwe
Faulting package-relative application ID: App

...and:
The server Microsoft.WindowsCalculator_10.1905.28.0_x64__8wekyb3d8bbwe!App did not register with DCOM within the required timeout.

Other apps show similar issues.

I thought about uninstalling/reinstalling apps, but the Microsoft Store is broken as well, so I probably couldn't reinstall.

Any ideas? SFC and DISM (Run Dism /Online /Cleanup-Image /RestoreHealth) show no errors

- - - Updated - - -

Just to add another few data points... I ran the "Appsdiagnostic10.diagcab" tool from Microsoft and it crashed


Next I created a new user profile. The apps worked under that profile but not under mine.

Try the Windows Store Apps troubleshooter at the bottom of Settings, Update & Security, Troubleshoot:

Run and Use Windows Store Apps Troubleshooter in Settings

You are a lifesaver. I was almost at the place of considering a profile migration.

I had to reset most all of my apps, and used that opportunity to uninstall the ones I never use. Oddly 2 of them (Camera and Photos) had the uninstall button grayed out... after some googling, I had to use Powershell to purge those.

Thank you! Have a beer on me