I am backing up one of my virtual machines that's running on Hyper-V 2008 R2.  I am using Windows Backup software.  It does an incremental backup of the entire VM every night.  When I look at the backup location, it is creating two large files.  One is a VHD file and the other is a AVHD file.  Both are about 250 GB each.  I don't have any snapshots.  The VM itself has a 185 GB VHD file and no AVHD file.  Why is it creating an AVHD file as part of the backup?  What can I do to

Hi Kevin,

As you said AVHD should be created when creating snapshots. As you mentioned "backup VM", are you backing up from Hyper-V Host or inside VM?

I tried to build a server for incremental backups (inside VM), it creates 2 VHDX files and these 2 VHDX files keep increase when doing more backups. So no AVHD file is created.

In current situation please open Hyper-V, click on Inspect Disk, choose that AVHD file and see if it is created based on a specific VHD file. If not then you should able to remove it safely.