If you build a bunch of VM's for use in a Citrix VDI and it's not being fully utilized or the VM's rotated it might cause the VM's that are never used to stop responding to AD and when they do come online the VM shows as Unregsitered in Citrix Studio.
In my situation, the computer account basically expired by never reporting back to AD. The only solution is to reset the computer account so it registers again.
You can tell that you have the same problem when you try to login as an admin in the VM and you are presented with "The trust relationship between this workstation and the primary domain failed" and if you check the network adapter on the bottom right of the login screen it will show "Unauthenticated."
- Make sure the VM that has the issue is turned off
- Login to the Citrix Provisioning server and start the Citrix Provisioning Console and connect to the server
- Go to Sites > Site > Device Collections and select the collection that contains the VM
- Right click on the VM that has the issue > Active Directory > Reset machine Account Password
- If the VM is still active even though you turned it off, just right-click it and select Mark Device Down
- Start the VM up again and the VM should report back as registered and no longer show Unauthenticated in the network adapter