Login-Status in Office365 ermitteln?

# Check O365 Login Status
# (c) 2024, M. Zurhorst
#

## Check for the availability of the SignedOut property underneath the ..\Identities\*_ADAL registry key  
## and catch the exception when this property does not exist
try { $prop = Get-ItemProperty -Path 'HKCU:\SOFTWARE\Microsoft\Office\16.0\Common\Identity\Identities\*_ADAL' -Name SignedOut -ErrorAction Stop }  
catch [System.Management.Automation.PSArgumentException] { $prop = 0 }


if($prop -eq 0) { Write-Host "User is authenticated. Ending ..." }  
else {
	Write-Host "User is not authenticated!`n`nLaunching noticiation popup ..."  

	# Determine current user for error message
	$CurrentUser = (Get-WMIObject -ClassName Win32_ComputerSystem).Username.Split('\')[1]  

	# Load the PresentationFramework module required for the message box
	Add-Type -AssemblyName PresentationFramework

	# Display Messagebox when User is not logged into O365
	# User shall decide whether or not login into Office is desired.
	$msgBoxInput =  [System.Windows.MessageBox]::Show("You (" + $CurrentUser + ") are currently not authenticated in Office365.`nThis may cause issues in COMOS release workflows.`n`nWould you like to launch Excel to (re-)authenticate?",'Warning: O365 Authentication missing','YesNo','Warning')  

	switch  ($msgBoxInput) {

	'Yes' {  
		
		## We launch Excel; the user shall now authenticate
		Start-Process 'C:\Program Files\Microsoft Office\root\Office16\EXCEL.EXE'  
	
	}

	'No' {  
	
		## We do nothing and respect the user decision! 
	
	}
	}

}