TLDR - Azure Virtual Desktop Black Screens. Could be 2 Min long, could be much longer. Tried removing stuck profiles, spun up all new VMs to see if that would fix it, finally disabled an application service that was polluting the Event logs constantly with appcrashes. Hoping that maybe the event logs weren't able to keep up so we had a black screen while events caught up. Grasping at straws.
We started getting reports of black screens when users login to one of our AVD Host Pools. Our users are using FSLogix for profiles, but we've also seen the issue when logging via RDP with a local admin account. We tested and saw similar results where you login, FSLogix Prompt goes by, then to Preparing Windows, then black screen.
- In a normal login, this black screen will last 10-20 seconds before desktop comes available and user can begin their session.
- With this issue, we were seeing black screens that just stayed there until you forced a logout of your account.
We saw some profile issues with the VMs in the pool appearing to be stuck on a VM when it should be removed upon logoff with FSLogix and we saw some stuck local_username FSLogix profiles still in the users folder. Instead of finding the needle in a haystack, we spun up a new group of VMs and put the others in drain mode / excluded.
With the new VMs, logins from RD Client were working fine yesterday afternoon, evening and this AM. But later in the morning, we saw some issues with users getting a black screen lasting 90 sec - 2 min before desktop loaded in. I had it happen to me when logging in, but it seemed to go away once I tried a couple more times. I even directly RDPd into the host that I had the 2 min black screen for me and was able to get in quickly. So issue appears to still be showing, but not as bad.
We looked in event logs and saw that one particular application - the Aspen Multicase Web service was polluting the service event logs with appcrash errors every few seconds. So we've disabled that application service on all the VMs in the pool and logins have been normal since. We read event logs that were event 4625 (failed login) but the event said event logs couldn't keep up and needed to stop duplicate events...so we were thinking that this service was constantly writing to event logs, could the slow logins happen when the service is trying to run, failing and writing to event logs. the logs wouldn't be able to write the login info.
But every other change we made things seem fine afterward for a while, but then the black screen will come back for at least 90sec - 2 min.
Any suggestions on things we can try / look at that could be causing this?
