For those new to vSphere 5's GUI, there's a new column that's been added to the Virtual Machine view by the name of "Needs Consolidation".
This option was put in due to the occasional problem when Snapshots did not delete properly and would leave the delta files remaining in the VM's folder while the Snapshot Manager would show no snapshots existing.
With this option added to the columns, you should also take note of the option within the Snapshot options for each VM which will now allow a user to select the "Consolidate" function
As noticed with the first screenshot, we had a couple systems which were requiring some consolidation to them. So another admin went through and hit the consolidated button and got hit with a "Unable to access file
18 deltas... 18! Regardless of the vmsn file in there, there was no record of there being any snapshots.
In this case, that system probably hasn't even been rebooted 18 times much less been snapshot that many times... Except, vDR (VMware Data Recovery) is setup on it to do daily snaps. So I checked the vDR appliance settings and I found 8 disks too many attached.
After removing all of those extra hard disks, the consolidations would succeed. Note, it took a while, but they did succeed.
Just another reminder of while vDR is a great tool to have on hand, it should definitely not be the one and only method of backup