Thanks for the suggestions
Adding -AllowRebootPassThru didn’t work as it isn’t an option Start-ADTProcess supports and PSAppDeployToolkit errored with a A parameter cannot be found that matches name 'AllowRebootPassThru' but switching the Uninstall to Uninstall-ADTApplication worked.
Using the command Uninstall-ADTApplication -Name "SQL Server Management Studio 21" -ApplicationType "EXE" -AdditionalAgrumentList "--quiet" runs, what looks like, the exact same command I was originally using but this time when the application uninstall action was completed the Post-Uninstall actions ran as expected ![]()
Thanks