While creating VM's using MCS, we see the master image copied and preparation VM created successfully on the VSAN. However while creating the VM's we fail with the following error in error log,

"A general system error occurred: PBM error occurred during PreProcessReconfigureSpec: pbm.fault.PBMFault; Error when trying to run pre-provision validation; Invalid entity"

• XenApp/XenDesktop 7.12 has a fix for this and will get you past the virtual machine creation issue.
• However we have observed that post the machine catalog creation on 7.12/7.13/7.14, if you try to update the catalog with an updated master image, it fails with the same PBM error. We have a bug filed for this issue currently and is being worked upon. Reference - LC7860 
• The workaround to this problem until the bug is fixed is to recreate the machine catalog with the updated master image.

Problem Cause

XenApp/XenDesktop 7.8 does not support vSAN.