During a Veeam backup I was alerted that one of our virtual machines had shutdown. The components concerned were: ESXi 5.5 U2, vCenter 5.5 U2, Veeam 8.0, 

It appeared during the backup routine a snapshot/consildation failed.

When trying to power back up I had the following error:

​An error was received from the ESX host while powering on VM webhost-1.
Failed to start the virtual machine.
Module DiskEarly power on failed.
Cannot open the disk '/vmfs/volumes/52962346-ce436dc0-05c7-b8ac6f98410c/twebhost-1/webhost-1.vmdk' or one of the snapshot disks it depends on.
Could not open/create change tracking file 

 

To get around this. SSH to the ESXi host:

1) # cd /vmfs/volumes/52962346-ce436dc0-05c7-b8ac6f98410c/twebhost-v1

2) # mkdir temp

3) # mv *.ctk.vmdk temp/

4) # mv *.nvram temp/

5) Power on the VM via the web or vsphere client.