ErrorWorld

Ever needed to know if a reboot is pending on your computer? Try this Microsoft/Scripting Guy PowerShell script, and you’ll know!

Copy the code below and save as .ps1 file, and execute at your convenience.

Function Get-PendingReboot
{
<#
.SYNOPSIS
    Gets the pending reboot status on a local or remote computer.

.DESCRIPTION
    This function will query the registry on a local or remote computer and determine if the
    system is pending a reboot, from either Microsoft Patching or a Software Installation.
    For Windows 2008+ the function will query the CBS registry key as another factor in determining
    pending reboot state.  "PendingFileRenameOperations" and "Auto Update\RebootRequired" are observed
    as being consistant across Windows Server 2003 & 2008.
  
    CBServicing = Component Based Servicing (Windows 2008)
    WindowsUpdate = Windows Update / Auto Update (Windows 2003 / 2008)
    CCMClientSDK = SCCM 2012 Clients only (DetermineIfRebootPending method) otherwise $null value
    PendFileRename = PendingFileRenameOperations (Windows 2003 / 2008)

.PARAMETER ComputerName
    A single Computer or an array of computer names.  The default is localhost ($env:COMPUTERNAME).

.PARAMETER ErrorLog
    A single path to send error data to a log file.

.EXAMPLE
    PS C:\> Get-PendingReboot -ComputerName (Get-Content C:\ServerList.txt) | Format-Table -AutoSize
  
    Computer CBServicing WindowsUpdate CCMClientSDK PendFileRename PendFileRenVal RebootPending
    -------- ----------- ------------- ------------ -------------- -------------- -------------
    DC01     False   False           False      False
    DC02     False   False           False      False
    FS01     False   False           False      False

    This example will capture the contents of C:\ServerList.txt and query the pending reboot
    information from the systems contained in the file and display the output in a table. The
    null values are by design, since these systems do not have the SCCM 2012 client installed,
    nor was the PendingFileRenameOperations value populated.

.EXAMPLE
    PS C:\> Get-PendingReboot
  
    Computer     : WKS01
    CBServicing  : False
    WindowsUpdate      : True
    CCMClient    : False
    PendComputerRename : False
    PendFileRename     : False
    PendFileRenVal     : 
    RebootPending      : True
  
    This example will query the local machine for pending reboot information.
  
.EXAMPLE
    PS C:\> $Servers = Get-Content C:\Servers.txt
    PS C:\> Get-PendingReboot -Computer $Servers | Export-Csv C:\PendingRebootReport.csv -NoTypeInformation
  
    This example will create a report that contains pending reboot information.

.LINK
    Component-Based Servicing:
    http://technet.microsoft.com/en-us/library/cc756291(v=WS.10).aspx
  
    PendingFileRename/Auto Update:
    http://support.microsoft.com/kb/2723674
    http://technet.microsoft.com/en-us/library/cc960241.aspx
    http://blogs.msdn.com/b/hansr/archive/2006/02/17/patchreboot.aspx

    SCCM 2012/CCM_ClientSDK:
    http://msdn.microsoft.com/en-us/library/jj902723.aspx

.NOTES
    Author:  Brian Wilhite
    Email:   bcwilhite (at) live.com
    Date:    29AUG2012
    PSVer:   2.0/3.0/4.0/5.0
    Updated: 01DEC2014
    UpdNote: Added CCMClient property - Used with SCCM 2012 Clients only
       Added ValueFromPipelineByPropertyName=$true to the ComputerName Parameter
       Removed $Data variable from the PSObject - it is not needed
       Bug with the way CCMClientSDK returned null value if it was false
       Removed unneeded variables
       Added PendFileRenVal - Contents of the PendingFileRenameOperations Reg Entry
       Removed .Net Registry connection, replaced with WMI StdRegProv
       Added ComputerPendingRename
#>

[CmdletBinding()]
param(
  [Parameter(Position=0,ValueFromPipeline=$true,ValueFromPipelineByPropertyName=$true)]
  [Alias("CN","Computer")]
  [String[]]$ComputerName="$env:COMPUTERNAME",
  [String]$ErrorLog
  )

Begin {  }## End Begin Script Block
Process {
  Foreach ($Computer in $ComputerName) {
  Try {
      ## Setting pending values to false to cut down on the number of else statements
      $CompPendRen,$PendFileRename,$Pending,$SCCM = $false,$false,$false,$false
      
      ## Setting CBSRebootPend to null since not all versions of Windows has this value
      $CBSRebootPend = $null
            
      ## Querying WMI for build version
      $WMI_OS = Get-WmiObject -Class Win32_OperatingSystem -Property BuildNumber, CSName -ComputerName $Computer -ErrorAction Stop

      ## Making registry connection to the local/remote computer
      $HKLM = [UInt32] "0x80000002"
      $WMI_Reg = [WMIClass] "\\$Computer\root\default:StdRegProv"
            
      ## If Vista/2008 & Above query the CBS Reg Key
      If ([Int32]$WMI_OS.BuildNumber -ge 6001) {
        $RegSubKeysCBS = $WMI_Reg.EnumKey($HKLM,"SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\")
        $CBSRebootPend = $RegSubKeysCBS.sNames -contains "RebootPending"    
      }
              
      ## Query WUAU from the registry
      $RegWUAURebootReq = $WMI_Reg.EnumKey($HKLM,"SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\")
      $WUAURebootReq = $RegWUAURebootReq.sNames -contains "RebootRequired"
            
      ## Query PendingFileRenameOperations from the registry
      $RegSubKeySM = $WMI_Reg.GetMultiStringValue($HKLM,"SYSTEM\CurrentControlSet\Control\Session Manager\","PendingFileRenameOperations")
      $RegValuePFRO = $RegSubKeySM.sValue

      ## Query ComputerName and ActiveComputerName from the registry
      $ActCompNm = $WMI_Reg.GetStringValue($HKLM,"SYSTEM\CurrentControlSet\Control\ComputerName\ActiveComputerName\","ComputerName")      
      $CompNm = $WMI_Reg.GetStringValue($HKLM,"SYSTEM\CurrentControlSet\Control\ComputerName\ComputerName\","ComputerName")
      If ($ActCompNm -ne $CompNm) {
    $CompPendRen = $true
      }
            
      ## If PendingFileRenameOperations has a value set $RegValuePFRO variable to $true
      If ($RegValuePFRO) {
        $PendFileRename = $true
      }

      ## Determine SCCM 2012 Client Reboot Pending Status
      ## To avoid nested 'if' statements and unneeded WMI calls to determine if the CCM_ClientUtilities class exist, setting EA = 0
      $CCMClientSDK = $null
      $CCMSplat = @{
    NameSpace='ROOT\ccm\ClientSDK'
    Class='CCM_ClientUtilities'
    Name='DetermineIfRebootPending'
    ComputerName=$Computer
    ErrorAction='Stop'
      }
      ## Try CCMClientSDK
      Try {
    $CCMClientSDK = Invoke-WmiMethod @CCMSplat
      } Catch [System.UnauthorizedAccessException] {
    $CcmStatus = Get-Service -Name CcmExec -ComputerName $Computer -ErrorAction SilentlyContinue
    If ($CcmStatus.Status -ne 'Running') {
        Write-Warning "$Computer`: Error - CcmExec service is not running."
        $CCMClientSDK = $null
    }
      } Catch {
    $CCMClientSDK = $null
      }

      If ($CCMClientSDK) {
    If ($CCMClientSDK.ReturnValue -ne 0) {
      Write-Warning "Error: DetermineIfRebootPending returned error code $($CCMClientSDK.ReturnValue)"    
        }
        If ($CCMClientSDK.IsHardRebootPending -or $CCMClientSDK.RebootPending) {
      $SCCM = $true
        }
      }
      
      Else {
    $SCCM = $null
      }

      ## Creating Custom PSObject and Select-Object Splat
      $SelectSplat = @{
    Property=(
        'Computer',
        'CBServicing',
        'WindowsUpdate',
        'CCMClientSDK',
        'PendComputerRename',
        'PendFileRename',
        'PendFileRenVal',
        'RebootPending'
    )}
      New-Object -TypeName PSObject -Property @{
    Computer=$WMI_OS.CSName
    CBServicing=$CBSRebootPend
    WindowsUpdate=$WUAURebootReq
    CCMClientSDK=$SCCM
    PendComputerRename=$CompPendRen
    PendFileRename=$PendFileRename
    PendFileRenVal=$RegValuePFRO
    RebootPending=($CompPendRen -or $CBSRebootPend -or $WUAURebootReq -or $SCCM -or $PendFileRename)
      } | Select-Object @SelectSplat

  } Catch {
      Write-Warning "$Computer`: $_"
      ## If $ErrorLog, log the file to a user specified location/path
      If ($ErrorLog) {
    Out-File -InputObject "$Computer`,$_" -FilePath $ErrorLog -Append
      }        
  }      
  }## End Foreach ($Computer in $ComputerName)      
}## End Process

End {  }## End End

}## End Function Get-PendingReboot

Source: Microsoft Script Center