Citrix XenServer 7 shows VMs created with XenDesktop 7.12 MCS as I/O not optimized

After upgrading to XenDesktop 7.12 VMs show I/O not optimized and Install I/O drivers and Management Agent when they are created using MCS.

When checking the master VM everything was fine:

If you try to google for the problem, you only find hints to reboot the VM several times to fix it – not helpful on pooled (random) machines. Thus I restarted the Master-VM several times, created a new Snapshot and applied it to the Machine Catalog. This did not solve the problem. I opened a Ticket at Citrix. Luckily they already knew the problem and gave me a hotfix to solve it. The hotfix replaces the following files:

C:\Program Files\Common Files\Citrix\HCLPlugins\Hypervisor\v2.20.0.0\XenServer
HypervisorsCommon.dll
XenServerPlugin

To replace them you need to stop the following services:

Citrix Host Service
Citrix Machine Creation Service
Broker Service

Don’t forget to Backup the existing ones before adding the Hotfix ones.

After replacing the files start the stopped services. Now you need to create a new Machine Catalog – otherwise the fix will not work.

That’s it – to get the fix open a ticket at Citrix and reference to private LC6769.