Step by Step Directions for Techs
While you may think that if you merged your Hyper-V snapshots, you shouldn’t have AVHD files with your VHD files. For the record, the AVHD files are snapshot files used by Hyper-V to store the changes to the VHD without committing them.
Provided you checked SCVMM (System Center Virtual Machine Manager) or the Hyper-V console and saw no snapshots associated with the VM, the AVHD is a hold over from a previous snapshot. But wait! Don’t delete it.
If you checked the file dates, you will see that the AVHD file is still actively being written to and the VHD file is still frozen. To fix this, shut down the host and wait. You will see it start merging the files together and it will remove the AVHD when it is fun. I understand that this may also work if you save the state.
While it isn’t convenient, you can win back quite a bit of space! Happy merging!