1-800-691-1991 | 9am - 8pm ET

Backup and Replicas of virtual machines running on ESXi 6.0.x with Change Block Tracking (CBT) enabled may not be recoverable


Leveraging VMware Changed Block Tracking (CBT) data supplied by VMware ESXi 6.0 can potentially render the data in backups or replicas inconsistent or corrupt.


This is a VMware ESXi issue in CBT logic that affects ESXi 6.0 through ESXi 6.0 Update 1a. It is resolved with VMware ESXi 6.0 patch ESXi600-201511001. Please see VMware KB article for additional information about the issue. 


Installing the patch alone is not sufficient, CBT reset is also required for all of your VMs. CBT reset is mandatory in every scenario, because existing CBT maps may already be inconsistent due to the original bug, which in turn may result in inconsistent full backups in future.

Please follow this article to reset CBT. Please note that performing Active Full backups cannot be considered as a substitute to CBT reset with this particular CBT bug.

More information

To download the patch, please go the VMware KB article KB2137545
Veeam Backup & Replication
Last Modified:
Please rate how helpful this article was to you:
5 out of 5 based on 1 ratings
Thank you for helping us improve!
An error occurred during voting. Please try again later.

Couldn't find what you were looking for?

Below you can submit an idea for a new knowledge base article.
Report a typo on this page:

Please select a spelling error or a typo on this page with your mouse and press CTRL + Enter to report this mistake to us. Thank you!

Spelling error in text

Knowledge base content request
By submitting, you agree that your personal data will be managed by Veeam in accordance with the Privacy Policy.

ty icon

Thank you!

We have received your request and our team will reach out to you shortly.


error icon

Oops! Something went wrong.

Please go back try again later.