Powershell CIM Instance MDM_AssignedAccess

Question

I'm having an issue configuring Windows 10 Kiosk mode recently. I am using the MDM bridge via powershell as directed here: https://learn.microsoft.com/en-us/windows/configuration/kiosk-mdm-bridge

$nameSpaceName="root\cimv2\mdm\dmmap"
$className="MDM_AssignedAccess"
$obj = Get-CimInstance -Namespace $namespaceName -ClassName $className
Add-Type -AssemblyName System.Web
$obj.Configuration = [System.Web.HttpUtility]::HtmlEncode(@"
<?xml version="1.0" encoding="utf-8" ?>
<AssignedAccessConfiguration xmlns="http://schemas.microsoft.com/AssignedAccess/2017/config">
  <Profiles>
    <Profile Id="{9A2A490F-10F6-4764-974A-43B19E722C23}">
      <AllAppsList>
        <AllowedApps>
          <App AppUserModelId="Microsoft.ZuneMusic_8wekyb3d8bbwe!Microsoft.ZuneMusic" />
          <App AppUserModelId="Microsoft.ZuneVideo_8wekyb3d8bbwe!Microsoft.ZuneVideo" />
          <App AppUserModelId="Microsoft.Windows.Photos_8wekyb3d8bbwe!App" />
          <App AppUserModelId="Microsoft.BingWeather_8wekyb3d8bbwe!App" />
          <App AppUserModelId="Microsoft.WindowsCalculator_8wekyb3d8bbwe!App" />
          <App DesktopAppPath="%windir%\system32\mspaint.exe" />
          <App DesktopAppPath="C:\Windows\System32\notepad.exe" />
        </AllowedApps>
      </AllAppsList>
      <StartLayout>
        <![CDATA[<LayoutModificationTemplate xmlns:defaultlayout="http://schemas.microsoft.com/Start/2014/FullDefaultLayout" xmlns:start="http://schemas.microsoft.com/Start/2014/StartLayout" Version="1" xmlns="http://schemas.microsoft.com/Start/2014/LayoutModification">
                      <LayoutOptions StartTileGroupCellWidth="6" />
                      <DefaultLayoutOverride>
                        <StartLayoutCollection>
                          <defaultlayout:StartLayout GroupCellWidth="6">
                            <start:Group Name="Group1">
                              <start:Tile Size="4x4" Column="0" Row="0" AppUserModelID="Microsoft.ZuneMusic_8wekyb3d8bbwe!Microsoft.ZuneMusic" />
                              <start:Tile Size="2x2" Column="4" Row="2" AppUserModelID="Microsoft.ZuneVideo_8wekyb3d8bbwe!Microsoft.ZuneVideo" />
                              <start:Tile Size="2x2" Column="4" Row="0" AppUserModelID="Microsoft.Windows.Photos_8wekyb3d8bbwe!App" />
                              <start:Tile Size="2x2" Column="4" Row="4" AppUserModelID="Microsoft.BingWeather_8wekyb3d8bbwe!App" />
                              <start:Tile Size="4x2" Column="0" Row="4" AppUserModelID="Microsoft.WindowsCalculator_8wekyb3d8bbwe!App" />
                            </start:Group>
                            <start:Group Name="Group2">
                              <start:DesktopApplicationTile Size="2x2" Column="2" Row="0" DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Accessories\Paint.lnk" />
                              <start:DesktopApplicationTile Size="2x2" Column="0" Row="0" DesktopApplicationLinkPath="%APPDATA%\Microsoft\Windows\Start Menu\Programs\Accessories\Notepad.lnk" />
                            </start:Group>
                          </defaultlayout:StartLayout>
                        </StartLayoutCollection>
                      </DefaultLayoutOverride>
                    </LayoutModificationTemplate>
                ]]>
      </StartLayout>
      <Taskbar ShowTaskbar="true"/>
    </Profile>
  </Profiles>
  <Configs>
    <Config>
      <Account>MultiAppKioskUser</Account>
      <DefaultProfile Id="{9A2A490F-10F6-4764-974A-43B19E722C23}"/>
    </Config>
  </Configs>
</AssignedAccessConfiguration>
"@)

Set-CimInstance -CimInstance $obj

It was working some weeks ago, but now kiosk mode is not being enforced and all the software is available. I stepped through the code, and now $obj is an empty variable. The result is powershell complaining "Configuration" is no longer a part of the object, which is reasonable because the variable is empty.

I verified some other common CIM classes against "Get-CimInstance" and they result fine. I verified the class does exist under that namespace, and properties does show a "Configuration" value:

Admittedly, this is my first time digging into manipulating CIM so it could be something very obvious I am not seeing. Research hasn't provided me squat. This is occurring on Windows 10 1909 and 20H2.

Appreciate any assistance.

Answer 1

So checking the value as the System user produces the correct result. Permissions issue in evaluating the CIM instance it seems.