Horizon Instant clones error vm.ctkEnabled

Today, I had an issue with a customer that had problems with their HorizonApps Instant clones farm.
While provisioning a new version of the image, it failed with the following error: Fault type is VC_FAULT_FATAL – A specified parameter was not correct: vm.ctkEnabled.

The customer already mentioned that they found the following KB article: https://kb.vmware.com/s/article/76280
But after applying the workaround they still had the same issue.

Master Image
Indeed they had set the correct advanced parameter changes to disable Change Block Tracking (CBT).


So after further investigation, we noticed that the instant clones replica VM did not have the vm.ctkEnabled on FALSE.
This was due to the fact that the customer’s backup solution, Dell Avamar changed this by default to TRUE for every new virtual machine created. This was a default behavior within their backup policy.

After modifying the policy and excluding replica templates, the provisioning of the desktop went without any issue!
I hope this short blog will hopefully help someone as I spend quite some time figuring this one out what the root cause was for the vm.ctkEnabled error.

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