Windows 10 1803 deployments no longer displays our custom login screen image until a user logs in and logs off. Instead, the computer displays a solid blue color screen. With our 1709 deployment the login screen image is displayed after the task sequence completes which is how the users know that the machines is finished with the image, but not on 1803.
I have temporarily created a task that runs after the main task sequence to login as a user, run gpupdate and log off. This appears to fix the issue. It will also fix itself after a regular user has logged in and logged off.
Update July 30, 2018 >> Microsoft confirms this is a design change, not a bug!
Part of a post from Jason E. in the Windows debug team
“It turns out this is an issue that was caused by a change in the Task Scheduler made in 1803 (as odd as that sounds). During the first boot after a deployment, the group policy does in fact make all the required changes for the policy to get applied. LogonUI successfully reads the policy data and starts going through the steps to apply the policy. One of these steps is to check to see if the Task Scheduler is up and running because one of the components it (LogonUI) uses is a task basked COM server. Turns out Task Scheduler is running, but is a state where it is not advertising itself as such (there is a named event LogonUI expects to be created and set, which is how it knows things are not quite ready). This is the point the applying of the logon and lock screen images fails out.
So.. why isn’t Task Scheduler getting up and running? Prior to 1803, the Task scheduler would execute scheduled tasks that were from the previous install (e.g. upgrade scenario) before the OS upgrade was really done. A change was made in 1803 to try to improve the reliability of the upgrade. The change was to not run these tasks until the first user had completed a logon. This is why this is only impacting the first boot after a deployment. While this should mean more reliable upgrades, it has caused the side effect.”
Update August 27, 2018 >>
The fix for this issue currently scheduled to ship in 2018.9C , which should be September 18th (barring any unforeseen circumstances). The issue also appears to be fixed in 1809.
Update September 20, 2018 >>
The patch has been released to fix this issue.
>>Microsoft releases Windows 10 builds 17134.319, 16299.697
>>Addresses an issue in which the lock screen shows a solid color instead of an image specified by a policy before a customer signs in for the first time.