Nun ist es natürlich schwer zu wissen, was du schon alles probiert hast und vermutlich kommen jetzt zuerst alle Prozeduren, die du schon versucht hast... oder auch nicht...
also in den meisten Fällen half eine der beiden folgenden Prozeduren...
Method 1:
Press Windows + X keys on the keyboard, select Command prompt (admin).
Enter the below commands one by one and hit Enter key.
PowerShell -ExecutionPolicy Unrestricted
It will open the PowerShell window.
Now enter the below command and hit Enter key.
Get-AppXPackage -AllUsers |Where-Object {$_.InstallLocation -like "*SystemApps*"} | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
If the issue still persist, follow the below method.
Method 2:
Open the Task manager. Here’s a tip: Press CTRL+Shift+ESC.
Click File > Run New Task
Make sure you have a check mark beside “Create this task with administrative privileges”
Type Powershell
Type the following in the Powershell prompt:
$manifest = (Get-AppxPackage Microsoft.WindowsStore).InstallLocation + '\AppxManifest.xml' ; Add-AppxPackage -DisableDevelopmentMode -Register $manifest
Close the Powershell window
Reboot the computer and check if it helps.