Sanity Check: At our company, we use Citrix Remote PC Access for the Admin Workstations, which are Lenovo ThinkCentre Tiny PCs. Every time a PC decommissioned I ask myself: How do I remove it from Studio? Because every f*#!6ng time, Studio tells me, there is an open session. Even months after the PC is gone. The only way I was able to help me so far, was to force delete them with PowerShell. Am I missing something obvious?

Are you able to remove it from the Delivery Group and then delete it?

I recently had the same issue with a RemotePC session, with my lab environment that had been offline for so long that Citrix hibernated my lab DaaS tenant and it still told me there was an active session! PowerShell was the only way.

@VTScott Forgot to reply. That was indeed the obvious step I was missing, as the error message was leading me in the wrong direction. We had to delete from Delivery Group first, wait a bit, and could clean up everything afterwards.