Sometime we see Backup failed for that VM with the error message :

Virtual disk configuration change detected, resetting CBT failed Details: A general system error occurred: 
Creating VM snapshot
Error: A general system error occurred: 

There are few documents which you can find for this error .I couldn’t reboot the host as this was a production cluster. After some homework, i figured out some ways to fix the issue.

1: Reboot the Virtual Machine.

This task will refresh the .vmx file and you will get your VM in a healthy state back again.

2: If this happens there is no guarantee that you will be able to recover the VM. So better have an older backup ready, and recover the Virtual machine.

3: The virtual machine’s .vmx configuration file can be reloaded from the command line. This operation does not generate a new Inventory ID (Vmid) for the virtual machine and allows it to stay in the same resource pool.

To resolve this issue, reload the virtual machine’s .vmx configuration file.

To reload the virtual machine’s .vmx configuration file, perform one of these options:

• Reload the configuration file of all the virtual machines on the ESXi/ESX host using a script by running this command:for a in $(vim-cmd vmsvc/getallvms 2>&1 |grep invalid |awk ‘{print $4}’|cut -d \’ -f2);do vim-cmd vmsvc/reload $a;done
  • Reload the .vmx configuration file from the command line:

  1. Log in to the Local Tech Support Mode console of the ESXi/ESX host.
  2. Obtain the Inventory ID (Vmid) for the virtual machine using this command:# vim-cmd vmsvc/getallvms

     Note: The output shows virtual machines which are registered on the ESXi/ESX host.

     You see output similar to:

     Vmid Name File Guest OS Version Annotation
2848 Test.vmx winNetEnterpriseGuest vmx-07 To be used as a template

     In this example, the Vmid is 2848.

  3. Reload the .vmx file using this command:# vim-cmd vmsvc/reload Vmid

  Either of the steps should work to fix the issue.