How to Find GPO Drive Mapping

When moving data to a new file structure, e.g. when implementing DFS, you need to update all references.

Data references are typically found in GPO‘s with settings for drive mapping and Software Distribution.

Many other references may exist such as, Excel sheet references, generic script references, etc.

For now we’ll be focusing on:

GPO’s with drive mapping

Check this article for information on how to find and edit GPO’s with software distribution.

For detailed instructions on how you can create your own GPO analysis scripts read this.

Using PowerShell to Identify GPO Drive Mapping

In an old domain with a long history it may be difficult to find all policies that reference the data you’re moving.

To make sure you don’t miss anything it makes good sense to jump into some PowerShell’ing.

Use the following script to identify all drive mappings found in the GPO’s of your domain:

$Reports = Get-GPO -All | Get-GPOReport -ReportType Xml
$DriveMappings = @()
ForEach ($Report In $Reports) {
  $GPO = ([xml]$Report).GPO
  $LinkCount = ([string[]]([xml]$Report).GPO.LinksTo).Count
  $Enabled = $GPO.User.Enabled
  ForEach ($ExtensionData In $GPO.User.ExtensionData) {
    If ($ExtensionData.Name -eq "Drive Maps") {
      $Mappings = $ExtensionData.Extension.DriveMapSettings.Drive
      ForEach ($Mapping In $Mappings) {
        $DriveMapping = New-Object PSObject -Property @{
          GPO         = $GPO.Name
          LinkCount   = $LinkCount
          Enabled     = $Enabled
          DriveLetter = $Mapping.Properties.Letter + ":"
          Label       = $Mapping.Properties.label
          Path        = $Mapping.Properties.Path
        }
        $DriveMappings += $DriveMapping
      }
    }
  }
}
Write-Output $DriveMappings | ft GPO, LinkCount, Enabled, DriveLetter, Label, Path -AutoSize

The output from the script will look similar to this:

GPO             LinkCount Enabled DriveLetter Label           Path
---             --------- ------- ----------- -----           ----
Drive Mapping H         1 true    H:          Documents       \\fileserver1\data
Drive Mapping U         1 true    U:          Personal drive  \\fileserver1\homedir$\%LogonUser%
Drive Mapping G         0 false   G:          Company archive \\fileserver1\dokumenter$
Drive Mapping P         3 true    P:          Accounting      \\fileserver2\XAL
Drive Mapping I         0 false   I:          Branch files    \\fileserver2\infomenu

Once identified, review what GPO’s are referencing the data you’re moving. Then make a plan to update these GPO’s when doing the switch.

For a thorough primer on GPO, application order, filtering, etc., have a look at this article.