Server log shows: "VSS Error:..."

Server log shows: "VSS Error: Couldn't take snapshot (IVssBackupComponents::StartSnapshotSet: 0x80042316: Another shadow copy creation is already in progress"

• Cause: The Volume Shadow Copy Service (VSS) is unable to run due to another instance of VSS already running. The VSS subsystem supports multiple snapshots existing simultaneously, but only one can be created at a time.
• Solution: Retry the backup later, or reschedule the backup ahead or behind by 30 minutes.