I use a powershell script to configure Windows Unified Write Filter (UWF) and restart afterwards like this:
$NAMESPACE = "root\standardcimv2\embedded"
$objUWFFilter = Get-WMIObject -namespace $NAMESPACE -class UWF_Filter
# some configuration
$objUWFFilter.RestartSystem()
That worked fine unntil I switched to Windows LTSC 2021 where I get this error:
Exception calling "RestartSystem" : "Access denied "
At C:\Program Files (x86)\UWF_Control\UWF_Control.ps1:1837 char:17
+ $objUWFFilter.RestartSystem()
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : WMIMethodException
My workaround was using:
uwfmgr filter restart
That works on LTSC 2021 (10.0.19041) but not on LTSC 2019 (10.0.17763) where it drops this eror:
Restart request failed (Access is denied.)
What's going wrong. The WMI method seems to have disappeard and uwfmgr is missing rights although it is run as adminstrator.
While working with UWF I had to notice that neither uwfmgr.exe nor the WMI-objects provide all the UWF-features as described by Microsoft https://learn.microsoft.com/en-us/windows-hardware/customize/enterprise/uwfmgrexe
The test environment are identical virtual boxes with bare Windows installations. UAC is on, scripts are run with elevated rights. I tried it on a physical machine as well and again without success.
And somthing else is peculiar. A user can execute uwfmgr filter get-config if UWF protection is disabled. However, if enabled the elevation is required, oterhwise the user gets the "Acccess is denied" error.
