Start-WUOfflineScan.ps1

Function Start-WUOfflineScan {
<#
    .SYNOPSIS
        Start an offline WUA scan

    .DESCRIPTION
        Start an offline WUA (Windows Update Agent) scan using wsusscn2.cab.

    .PARAMETER FilePath
        Specifies the path to the wsusscn2.cab file to be used to perform the offline scan.

    .PARAMETER IncludeSupersededUpdate
        Specifies to include superseded updates in the results if any.

    .EXAMPLE
        Start-WUOfflineScan -FilePath C:\temp\wsusscn2.cab -Verbose

    .NOTES

    You can get the offline wsusscn2.cab from:
    http://download.windowsupdate.com/microsoftupdate/v6/wsusscan/wsusscn2.cab

    Official doc is:
    https://docs.microsoft.com/en-us/windows/win32/wua_sdk/using-wua-to-scan-for-updates-offline

#>
[CmdletBinding()]
Param(
[Parameter(Mandatory)]
[ValidateScript({Test-Path -Path $_ -PathType Leaf})]
$FilePath,

[switch]$IncludeSupersededUpdate
)
Begin {

    if ($FilePath -match '^~') {
        $FilePath = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($FilePath)
    }

    try {
        $UpdateSvc = New-Object -ComObject Microsoft.Update.ServiceManager

    } catch {
        Write-Warning -Message "Failed to query if server is configured against a WSUS server because $($_.Exception.Message)"
    }

    Function Test-WUARebootRequired {
        try {
            (New-Object -ComObject 'Microsoft.Update.SystemInfo').RebootRequired
        } catch {
            Write-Warning -Message "Failed to query COM object because $($_.Exception.Message)"
        }
    }
}
Process {
    if (-not(Test-WUARebootRequired)) {
        try {
            # Create a session
            $Session = New-Object -ComObject Microsoft.Update.Session

            # Import the the offline cab
            $UpdateService = $UpdateSvc.AddScanPackageService('Offline Sync Service',"$($FilePath)", 1)

            $Searcher = $Session.CreateUpdateSearcher()
            $Searcher.ServerSelection = 3 #ssOthers

            if ($IncludeSupersededUpdate) {
                $Searcher.IncludePotentiallySupersededUpdates = $true
            }
            $Searcher.ServiceID = $UpdateService.ServiceID.ToString()

            $Criteria = "IsInstalled=0 and DeploymentAction='Installation' or IsPresent=1 and DeploymentAction='Uninstallation' or IsInstalled=1 and DeploymentAction='Installation' and RebootRequired=1 or IsInstalled=0 and DeploymentAction='Uninstallation' and RebootRequired=1"

            # Search for updates
            $SearchResult = $Searcher.Search($Criteria)

        } catch {
            Write-Warning -Message "Failed to search for missing updates because $($_.Exception.Message)"
            if ($SearchResult) {
                Write-Warning -Message "The search result status code was $($SearchResult.ResultCode)"
            }
            break
        }
        if ($SearchResult.ResultCode -eq 2) {

            # Output what was found
            if (($SearchResult.Updates).Count -ne 0) {

                $SearchResult.Updates |
                ForEach-Object {
                    Write-Verbose -Message "Missing update: $($_.Title)"
                    $_
                }
            } else {
                Write-Verbose -Message 'There are no updates to install' -Verbose
            }
        } else {
            Write-Warning -Message 'Failed to search for updates'
            Write-Warning -Message "The search result status code was $($SearchResult.ResultCode)"
        }
    } else {
        Write-Warning -Message 'A reboot is pending'
    }
}
End {}
}