VMware View: The registration of the Group Policy Client service failed

The problem does not really fit here, but maybe it will help someone. The following problem occurs with users who have not logged on to VMware View Horizon Desktops for a long time:

The registration of the Group Policy Client service has failed. Access denied

The error occurs because the NTUser.dat file within the user profile is corrupt. This can usually be recognized by the size of exactly 256KB. Deleting the NTUser.dat helps so that the user can log on again, but does not resolve the cause.

The error occurs if the following situation applies: The user's view profiles are located on a file server with Windows Server 2012 as the operating system and deduplication activated.

The cause of the problem is the Windows 2012 feature "Deduplication", which causes the problems with the NTUser.dat. Apparently only switching off and "de-duplicating" helps here. Deduplication can be undone with PowerShell:

Start-DedupJob -Volume p: -Type Unoptimization

The status of the job can be checked with the following command:

Get-DedubJob

Depending on the amount of data, the job can take quite a long time to complete. Furthermore, deduplication must be switched off for the corresponding volume:

Profiles with broken NTUser.dat can also be found using PowerShell:

Get-ChildItem ntuser.dat -Recurse -Force -ea 0 | where {$_.Length -le 262144} | foreach {$_.fullname}