Starting a process from within a OOP BG task is not possible in Windows Enterprise

[JosHuybrighs]

My WinUI/WinAppSDK desktop application uses a background task that is triggered when a portable storage device, e.g. a USB flashdrive, is inserted (task type deviceUse in the manifest file). If the device is recognized as one that is configured in the app the task starts the main app without a window being created to sync a source location to the USB device. The sync operation is done in the main app and not in the background task because it can take longer than 30s to complete.

The issue is that this works without problems on Windows Home and Pro but not on Windows Enterprise.
The background task is an OOP C#/WinRT BG task because task type deviceUse is not supported in Inproc COM background tasks.

The main app is started using LaunchFullTrustProcessForCurrentAppAsync. I tried to do the same using Process.Start() which returns successfully but doesn't start the process on none of the 3 Windows types. I also tried to logon the user in code by means of LogonUser (in advapi32.dll) but that of course is not supported in a C#/WinRT component.

I have a number of questions/remarks about this:

• The OOP BG task runs under LowIL and IsAuthorized in WindowsIdentity.GetCurrent() is set to False. I assume that this is the reason that it doesn't work in Windows Enterprise but why is it then OK in Windows Home and Pro? Is this by accident?
• I know that if I would do the same with a InProc COM BG task this will work accross all Windows types. IsAuthorized will be True then. I have tested this with a InProc COM BG task that is triggered on a timer.
• Is there an alternative method for a background task to trigger a process when something has to be done that can take longer than 30s and still have the possibility to publish the app on the Microsoft Store?