KB ID : 105007
Products :
Published : March 29, 2016
Created : March 29, 2016
Last Modified : June 26, 2016


This error message occurs if Changed Block Tracking was not enabled for the virtual machine and hence, its not possible to backup the VM.


To overcome the error message, please ensure that the virtual machine is configured with the below prerequisites:

1) The ESX/ESXi host in which the VM available should be version 4.0 or more.

2) The VM’s hardware version should be 7 or more.

3) If the above two prerequisites are fulfilled, then enable CBT for the VMs by following the below steps:

  • Power off the virtual machine.
  • Right-click the virtual machine and click Edit Settings.
  • Click the Options tab.
  • Click General under the Advanced section and then click Configuration Parameters. The Configuration Parameters dialog opens.
  • Click Add Row.
  • Add the ctkEnabled parameter and then set its value to true.
  • Click Add Row, add scsi0:0.ctkEnabled, and set its value to true.

    Note: scsi0:0 in scsi0:0.ctkEnabled indicates the SCSI device assigned to the hard disk that is added to the virtual machine. Every hard disk added to the virtual machine is given a SCSI device that appears similar to scsi0:0, scsi0:1, or scsi 1:1. CBT is enabled (or disabled) individually on each disk.

  • Power ON the virtual machine.

  • In the home directory of the virtual machine, verify that each disk having CBT enabled has also a vmname-ctk.vmdk file.
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