Old one this but during deploying a new W7 VDI image I found that randomly, the deployed images would present the user with a popup like this at logon which was not present on the golden master:
This turned out to be caused by the gold image being on a Vmware host with a given CPU type and the “failing” deployed images were being spun up on a host in the cluster with a different CPU in the host.
EVC is enabled but this only works at vmotion level. Differing CPUs in the hosts in a given cluster still present the real hardware CPU type to the guests.
That explained why it didn’t occur all the time, only some of the time, as they had a 3 host cluster, 2 the same, one different.
The fix? Spin up the gold image on all different CPUs in the cluster and reboot after each hardware detection has completed, this way the image has all CPU profiles loaded and doesn’t moan when its deployed.