I’ve recently had a crash on one of my VMWare 5.1 hosts. When the next scheduled backup executed, I got the following error:
21/02/2013 2:02:28 a.m. :: Cannot use CBT: Soap fault. Error caused by file /vmfs/volumes/50bb131b-59817aa0-f7e5-6cae8b1b67ca/test/test01.vmdkDetail: '', endpoint: '
There is an article on the Veeam site KB1113.
The CBT file tracks changes when doing block level backups and is enabled when you do your first backup.
Changed Block Tracking (CBT) is a VMware feature that helps perform incremental backups. VMware Data Recovery uses this technology, and so can developers of backup and recovery software.
You can find out more information here.
You can safely ignore this error. However, if the issue continues, you will need to follow the instructions in KB1113.