This looks like it may be a known problem
It looks like this fix was implemented in the 8.11 patch bundle
Change Request: QCCR2A51456
The Data Protector backup session fails with the following error message:
|Critical| From: VEPALIB_VMWARE@hostname "" Time: <Date> <Time>
Backup failed because unable to utilize CBT as it was required.
|Major| From: VEPALIB_VMWARE@hostname "" Time: <Date> <Time>
|172:162| Virtual Machine "": No disk backed up...
Error: Backup failed because unable to utilize CBT as it
was required.
The 8.11 patch bundle has been superseded by 8.12, and can be downloaded from: