As a Citrix Administrator, you might be familiar (or at least should get familiar) with the administration aspects of the Provisioning Services (PVS). One of the most common tasks you will have to perform will be updating the PVS Master Image, be it new software installation or simple OS patching from time to time.
Doing so, in a very dynamic and demanding software environment, you might end up creating a new vDisk version and getting the message below, with regards to the limit of vDisk (differencing) versions:
What this actually means is that the number of differencing versions (.avhdx disks) built on top of the last base (merged .vhdx) vDisk image version, has exceeded the limit.
While there isn’t an enforced number of such vDisk versions, you need to set this up depending on the frequency of changes you perform, the storage tiers you use, the size of your storage, and so on.
To customize this, use the PVS Console, click on the root of the console, right-click the farm you want to configure, and select Properties. Next go to the vDisk Version Tab and configure the box “Alert if number of versions from base image exceeds:” . As a side note you can also configure the Default Access Mode for the new merged versions here.