AppReadiness Service and Black Screen

OffColour1972 

we were asked to put the following reg keys in place just this past Fri night (20201016) as we were experiencing this AppReadiness issue randomly in our Prod WVD env:

As a workaround, please set the below registry for the App Readiness preshell task and first logon’s timeout window to 30s to avoid the black screen for the first user’s logon.

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\AppReadinessPreShellTimeoutMs

Data Type: DWORD

Value: 0x7530       --> 30000ms = 30s

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\FirstLogonTimeout

Data Type: DWORD

Value: 0x1e         -> 30s

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\DelayedDesktopSwitchTimeout

Data Type: WDORD

Value: 0x1e -> 30s

Here's the explanation:

With the regkeys we do not wait on AppReadiness to load the Desktop Shell. The workaround should help to not run in Black Screen caused by the AppReadiness.

We did fixed the Black Screen issue with the KB4571744 in September 3rd. But may we hitting here different cause.

The best is to prepare the Windows 10 Client for Full Dump and create a dump after waiting 5 Minutes in black screen. This will help to go deeper in the analysis of the cause and problem resolution.

https://protect-us.mimecast.com/s/uQtaCmZkV9IEBDDSGEQ3u?domain=support.microsoft.com

We are not sure if this has helped or not yet as it is the first day these reg keys are in place and we'll have a bunch of people back in WVD, but I guess it kind of makes sense as we're now limiting the amount of time the AppReadiness service will run (30 secs) before allowing the session logon to continue, as far as I can tell anyway...