Tag Archives: HyperV

Merge Differencing Disks in HyperV 2012R2 / 2012

Merging differencing disks in Hyper-V 2012R2 is as easy as diskpart. Our new best friend 🙂 Follow the steps below and be upp and running in no time!

NB! The parent and the child VHD(X) must be Read/Write and NOT connected to VM guest. If alls well the child vmdisk WILL be deleted from storage!

  1. Open CommandLine (cmd) as Admin
  2. Dig down to you’re differencing disk image (VHD/VHDX)
  3. Type “diskpart
  4. Type “select vdisk file=<path to differencing disk image>
  5. Type “merge vdisk depth=1

How can this be?
When you create a differencing disk, there’s a parent-child relationship between the Virtual Hard Disk (VHD) files. The differencing disk contains only the changes from its master disk.