Hello Have you got any error messages when you opened calculator? "your computer can't upgrade to Windows 11" we could try to check the device manufacturer website whether this machine model is compatible with Windows 11.
- For the calculator, we could try to open powershell command line then run "Get-AppxPackage -allusers Microsoft.WindowsCalculator | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_. InstallLocation)\AppXManifest.xml"}" to register it.
- Or we could try to remove it from start menu by right click it then install it from Store again.
- We also could try to login with another account or create a new account then check it.
- We also could try to run powershell command line and run "get-appxpackage". Check the status of calculator app. If we got a status other than "OK", we could run "regedit" to open registry keys. Then navigate to the following location. Delete the registry key here. HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\AppModel\StateChange\PackageList For more troubleshooting information, we could check Event Viewer\Applications and Services\Microsoft\Windows\Apps log.