Problem Description
Backups are failing for Hyper-V servers with the error: "Multiple VMs with same UUID exists in cluster/scvmm".
Cause
This issue occurs when multiple virtual machines (VMs) with the same UUID exist on different hosts within the same Hyper-V cluster.
This typically happens if a VM is copied or imported to another host without changing its UUID, creating duplicates.
Since backup and management systems use UUIDs to uniquely identify VMs, duplicate UUIDs cause conflicts and result in backup failures.
Log Snippet
[2025-08-08 02:16:42,805] [ERROR] <_MainThread(MainThread)> Error <class 'inSyncLib.inSyncError.SyncError'>:
Multiple VMs with same UUID [C868567C-526E-4538-8E83-0256ECEEBB35] exists on different hosts
[u'XXXXXXXXA, u' XXXXXXXXB'] on cluster XXXXXXXXA (#100090013) (Error Code : HYPERV19).
Resolution
Identify Duplicate VMs
Use SCVMM, Hyper-V Manager, or another virtualization management tool to search for the UUID.
List all VMs with this UUID across the cluster.
Decide Which VM to Keep
Identify the original or active VM that should remain in the environment.
Remove or Reconfigure the Duplicate
Delete the duplicate VM or re-import it with a new UUID.
In Hyper-V, export and re-import the VM, ensuring you select the option to generate a new unique ID.
Refresh the Host List
After resolving duplicates, refresh the host/VM list in your backup or management software.
Retry the Backup
Once only one VM with the UUID remains, rerun the backup. It should complete without the HYPERV19 error.
Additional Notes
When cloning or migrating VMs, always ensure a new UUID is generated to prevent future conflicts.
This is a known behavior, and the software is designed to trigger this specific error code for easier troubleshooting.