Pass-Through Disks Detected (code 1912)

Situation

A Hyper-V backup plan terminates with the following warning: Pass-Through Disks detected. Pass-through disks were not backed up. Only recovery snapshots for virtual machines with pass-through disks were backed up. View the virtual machine list with pass-through disks:

Cause

Recovery checkpoint is the only content that is available for backing up on virtual machines with pass-through disks.

Solution

To back up a virtual machine with pass-through disks, you can use the following workaround: install a Backup instance straight to a virtual machine and back up separately.

To do this, proceed as follows:

1. Download the latest version of Backup for Windows.
2. Find the required virtual machine on a Hyper-V host.
3. Install a Backup for Windows instance on the virtual machine.
4. Create an image-based backup plan that includes all disk on the virtual machine.
5. Run this backup plan.