A BKP_SNAP snapshot remained and was viable in snapshot manger after a VMware backup failure. So it was necessary to delete the BKP_SNAP snapshot manually in snapshot manger of the vCenter server.
On competition of snapshot removal the BKP_SNAP snapshot was no long visible in snapshot manger of the vCenter server but there as a warning saying that consolidation was required on the VM the BKP_SNAP snapshot had been removed from.
Consolidation was run but it failed with the following:
An error occurred while consolidating disks: msg.fileio.lock
Powered down the VM tried consolidation again but this failed with the following:
An error occurred while consolidating disks: msg.snapshot.error-DISKLOCKED
Noticed that files relating to the snapshot remained in the VM folder on the data store.
VMware Ghost processes locked the snapshot files.
This was found by VMware engineer
Restart ESX server that has lock on the files.
It’s possible to find the mac-address of the host and target the "locker of the file". see VMware KB: Investigating virtual machine file locks on ESXi/ESX
If unable to find problem host as last resort I restart the services of all the hosts in that particular cluster which resolves it always
