Snapshot fails in ESXi “The virtual disk is either corrupted or not a supported format”

Question

We migrated all of our VMs to new storage using vMotion. However, one of our VMs, we had to move manually. Even though some data files didn't transfer over completely, the VM operates fine since the main vm files are available. However, when we take a snapshot using vSphere, the following error shows up "The virtual disk is either corrupted or not a supported format."

Answer 1

The best way I have found to fix problems with disks like this (and it's good that you can still read the VMDK file :-)) is to use a tool like GParted (the live CD) or Ghost to copy the contents of the disk over to a new VMDK file and replace the VMDK. The process I used the one time I had to do this was:

1. Create a couple backups of your data. With the VM having corrupt/missing data files you might want to copy all the VM files to your workstation or in another folder in the datastore.
2. Create a new virtual disk for the VM of the same size (or greater).
3. Boot from the GParted Live CD.
4. Using GParted copy the partition from the old disk to the new disk.
5. Shutdown the VM.
6. Remove both of the Virtual disks from the VM (making sure that "Remove from virtual machine and delete files from disk." is NOT checked).
7. Add a new virtual disk to the VM and select the option "Use an existing virtual disk" when prompted.
8. Boot the virtual machine and try taking a snapshot.

Answer 2

If you moved the files manually and you had a snapshot when you moved it you might want to check the parent and child IDs in the delta files, if the links don't line up right snapshots won't work properly.