Edit/Add GPO on DC via Powershell - powershell

Question

I'm given the task to migrate all the printers installed on workstations via GPO to another server.
As for now all printers are installed in a local decentralized Distribution Point, we want to move on a centralized Distribution Point/Print Server.
On mine DC, via Group Policy Management Editor, I've a lot of printers in
Computer Configuration\Preferences\Control Panel Settings\Printers
All printers are mapped from \DP00x\Printer and given a local name.
What i want to change is the \DP00x to \CentralDP01\Printer in the GPO.
I've managed via powershell to create all printer ports, install all printers and publish/list in the directory all of them.
Given that they are more than 100, I wish to automate the process to edit the GPO editing, so that i don't need to open each policy and each printer to modify the destination.
I've tried the cmdlet Get-GPRegistryValue because I know (at least) that printers are installed on HKLM\SYSTEM\CurrentControlSet\Control\Print\Printers
but i get this error every time:
Get-GPRegistryValue : The following Group Policy registry setting was not found: "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Printers".
Parameter name: keyPath
At line:1 char:1
+ Get-GPRegistryValue -Guid 6b464ed9-66c8-47fa-8327-1fe9b074a0d7 -Key H...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (Microsoft.Group...tryValueCommand:GetGPRegistryValueCommand) [Get-GPRegistryValue], ArgumentException
+ FullyQualifiedErrorId : UnableToRetrievePolicyRegistryItem,Microsoft.GroupPolicy.Commands.GetGPRegistryValueCommand
I tried as well Get-GPPrefRegistryValue
Get-GPPrefRegistryValue -Context Computer -Guid 6b464ed9-66c8-47fa-8327-1fe9b074a0d7 -Key HKLM\SYSTEM\CurrentControlSet\Control\Print\Printers
But error looks the same:
Get-GPPrefRegistryValue : The Preference registry setting "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Printers" was not found in the
"x-x-x-x-x-x" GPO in the x-x-x-x-x-x-x.com domain.
Parameter name: keyPath
At line:1 char:1
+ Get-GPPrefRegistryValue -Context Computer -Guid 6b464ed9-66c8-47fa-83 ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (Microsoft.Group...tryValueCommand:GetGPPrefRegistryValueCommand) [Get-GPPrefRegistryValue], ArgumentException
+ FullyQualifiedErrorId : UnableToRetrievePreferenceRegistryItem,Microsoft.GroupPolicy.Commands.GetGPPrefRegistryValueCommand
I found a workaround. Backup the GPO, manually edit the XML with the new value and import back the GPO.
I don't fancy the idea of manually editing because it can lead to errors and with over 100+ GPOs I can have alot of errors.
Can anyone help me?
Maybe i'm using the wrong commands, but so far documentations state to use GPO Module.

Answer 1

Unfortunately the GroupPolicy commands are limited to registry key settings only, and printer-preferences fall outside that. You can safely edit the live GPO xml files themselves though (or use Backup-GPO/Restore-GPO).
If you're only replacing the server name, this should work fine. Try it on a test GPO, updating the path as needed:
$guid = (Get-GPO -Name 'Test GPO')
# Check the GPO version before changes:
Get-GPO -guid $guid
$domain = 'domain.com'
$path = "\\$domain\SYSVOL\$domain\Policies\{$guid}\User\Preferences\Printers\Printers.xml"
# Update the path in the GPO xml:
(Get-Content $path -Raw) -replace 'DP00x','CentralDP01' | Set-Content $path
# Validate the GPO version/change date have updated - might take a while if xml is on a different DC:
Get-GPO -guid $guid