PROBLEM

In a Hyper-V cluster environment, backups of VM(s) fail with error:

This virtual machine cannot be backed up because it contains disks on both local volumes and cluster volumes (Error code 'HYPERVBACKUPCONTROLLER_003')

CAUSE

The VM's files are located on both CSV and non-CSV locations, which isn't supported by Microsoft Shadow Copy (VSS) and thereby fails with this error.

SOLUTION

It's important that not just the VHDX files are located on the CSV but even the other file types are placed on a CSV location. In fact the most common issue we see is the 'Current Configuration', being the XML file, placed on a non-CSV location.

1. The best way to check what's placed on a non-CSV location is to right-click on the VM > Move > Virtual Machine Storage. Next click on the '+' sign next to the VM and this will reveal the location of the VM's files.
   
   
2. In the 'Source Folder Path' column, you'll see the locations of all of the VM's files.

    

3. Any files not on the CSV location need to be moved to a CSV location, so drag and drop the file type onto the CSV location and then click 'Start'. 

   
   
   

4. Once all of the VM's files are located on a CSV location, you should be able to take a successful backup for this VM seeing as Microsoft Shadow Copy (VSS) would be able to run with this supported configuration.