This page documents a workaround to fix Azure Arc Update Manager assessments that hang or timeout, typically due to issues with the WindowsPatchExtension or agent state corruption.

1. Update assessments time out in the Azure Portal.
2. No recent update status from Arc-enabled servers.
3. `WindowsPatchExtension` or `WindowsOsUpdateExtension` appear stuck or in a failed state.

These steps reset the Arc update extension state by stopping services, removing cached extension data, and restarting the relevant components.

Run the following in a PowerShell session on the target computer (or via remote session with `Enter-PSSession`):

Stop-Service -name AutoAssessPatchesService
Stop-Process -Name "gc_arc_service" -Force
Stop-Process -Name "gc_extension_service" -Force
Stop-Process -Name "AutoAssessPatchService" -Force -ErrorAction SilentlyContinue
Remove-Item -Path "C:\Packages\Plugins\Microsoft.CPlat.Core.WindowsPatchExtension" -Recurse -Force
azcmagent extension remove -n WindowsPatchExtension
azcmagent extension remove -n WindowsOsUpdateExtension
Start-Service -Name "GCArcService"
Start-Service -name "ExtensionService"

You can run this from a Domain Controller or management server using PowerShell remoting. This assumes WinRM is enabled on target systems.

# List of computers
$computers = @("server01", "server02", "server03")
 
# Define the script block to execute on each remote computer
$scriptBlock = {
    try {
        Write-Host "[$env:COMPUTERNAME] Stopping services..." -ForegroundColor Cyan
 
        Stop-Service -Name AutoAssessPatchesService -ErrorAction SilentlyContinue
        Stop-Process -Name "gc_arc_service" -Force -ErrorAction SilentlyContinue
        Stop-Process -Name "gc_extension_service" -Force -ErrorAction SilentlyContinue
        Stop-Process -Name "AutoAssessPatchService" -Force -ErrorAction SilentlyContinue
 
        Write-Host "[$env:COMPUTERNAME] Removing extension files..." -ForegroundColor Cyan
        Remove-Item -Path "C:\Packages\Plugins\Microsoft.CPlat.Core.WindowsPatchExtension" -Recurse -Force -ErrorAction SilentlyContinue
 
        Write-Host "[$env:COMPUTERNAME] Removing Arc extensions..." -ForegroundColor Cyan
        azcmagent extension remove -n WindowsPatchExtension | Out-Null
        azcmagent extension remove -n WindowsOsUpdateExtension | Out-Null
 
        Write-Host "[$env:COMPUTERNAME] Starting Arc services..." -ForegroundColor Cyan
        Start-Service -Name "GCArcService" -ErrorAction SilentlyContinue
        Start-Service -Name "ExtensionService" -ErrorAction SilentlyContinue
 
        Write-Host "[$env:COMPUTERNAME] Done." -ForegroundColor Green
    } catch {
        Write-Warning "[$env:COMPUTERNAME] Failed: $_"
    }
}
 
# Loop over each computer and invoke the script remotely
foreach ($computer in $computers) {
    Write-Host "Processing $computer..." -ForegroundColor Yellow
    Invoke-Command -ComputerName $computer -ScriptBlock $scriptBlock -ErrorAction Continue
}

After running the workaround, you can reinstall the extension manually (or let Azure push it automatically):

azcmagent extension add --name WindowsPatchExtension

1. Only do this if you're sure assessments are hanging/stuck, not just delayed.
2. Check Arc logs and `C:\Packages\Plugins\Microsoft.CPlat.Core.WindowsPatchExtension\Status` for clues before running this.
3. May help to restart `azcmagent` if issues persist.