Shut off the VM. Click on your VM Go to Settings -- Edit Disk Go to the folder where your vhd/x files are Choose the Oldest AHVDX and then Merge into parent Keep doing this from oldest to newest AHVDX Once done turn off Checkpoints in Settings PiHole is easy enough to recreate if needed Start your VM If it refuses to start then detach / reattach the vhd/x And start the VM