Windows updates fail to install or rollback when UPL is enabled.

NOTE:
First make sure you are logged in as the local machine administrator and not a domain account. The UPL / user layer services monitor for a domain login and will block Windows updates in addition to controlling the behavior of many other Windows services.

SOLUTION:
If using a local machine account, set the "Citrix App Layering Guest Service" to Automatic start. The service should already be running, do not change the running state of the service.

Then proceed with the Windows update. The update should apply on the following reboot and the Layering guest service should have switched back to Running but Disabled start. If it has not then please change the Citrix App Layering Guest Service" back to Disabled start before using the image in production. Another supporting service will start and stop this service as needed.

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Problem Cause

The UPL services force dependency on various Windows services such as Windows update. This helps prevent Windows updates from being installed into a user layer. Installing updates in this manner is not a supported process and will likely fail to install or cause a variety of functional problems with that specific user layer if updates were allowed to be installed at that time.