Veeam – Task failed Error: Object with reference ‘vm-####’ was not found in hierarchy cache

Description of the Error

This error is often caused by removals or re-deployments of Virtual Machines that are manually targeted by Veeam Backup jobs.

Veeam backup jobs target the VMs in vSphere using the refID of the VM. If a VM is removed from vSphere, it’s refID is also destroyed, so the Veeam backup job will report the above error when it runs. Even if the VM is re-deployed with the same VM name, it will be assigned a different refID, and from Veeam’s perspective it will be a different VM.

Resolution

  1. In Veeam, edit the settings of the failing backup job
  2. In the virtual machines section, select the failing VM(s) and Remove them
  3. Click Add and locate the new instance of the VM. Click Add
  4. Click Finish to save your changes.

Best Practice

You can prevent this issue altogether by targeting VM folders in vSphere instead of the individual VMs. If the VMs within a targeted folder change, the Veeam backup job is able to process the change automatically and won’t error out.