Hyper-V brings to life several additional disaster recovery scenarios that can be leveraged to our advantage when the need arises. One of the features that really comes into play are VM snapshots. A Snapshot is basically a spot in time where the current
running configuration of the Virtual Machines is saved to a Snapshot Differencing Disk file (AVHD), from which you can return to from the future. This tip will show you how to manually merge hyper-v snapshots into a single VM for point in time restores.
When you create a differencing disk the original VHD is no longer modified and the snapshots are merged with the original vhd only when it is powered off. In disaster recovery scenarios, There may be cases where we want to manually merge snapshots ( avhd )
In order to do this, You must first change the extension of the Newest AVHD file to VHD.