The parent virtual disk has been modified since the child was created.

Scenario: You have a VM with a seperate disk having only system volume. While increasing system volume disk size (disk 1), it is recommended that there should not be any snapshot on VM. If you kept snapshot on VM then you get this warning message when you power on VM after inreasing the disk size.

Resolution:

1. Backup all files in VM folder in datastore to somewhere.

2. Delete snapshot from VM.

3. Remove all delta files from datastore folder in VM.

4. Remove all existing disk from VM. (Only dettach the disk from VM)

5. Add all disks again in order.

6. Power on VM.

VM will be successfully powered on.