Unable to Mount VeeamBackup_ Datastore - Specified Key, Name, or Identifier Already Exists

This error occurs when the vSphere Environment cannot create the 'VeeamBackup_' datastore because a datastore already exists with that name, or there is an entry stuck in the Datastore cache.

Note: The vPower NFS datastore stays mounted to the ESXi host. Each time you start an operation that would use the datastore, Veeam Backup & Replication checks whether the vPower NFS datastore is mounted to the host. If you manually unmounted the datastore or the datastore was unmounted by other causes, Veeam Backup & Replication remounts the datastore.

Initial Troubleshooting

Before proceeding to more advanced troubleshooting steps, determine if a datastore matching the name specified in the error is visible via a vSphere Client. If so, unmount it.

• Using the vSphere Web Client, connect to the vCenter that manages the ESXi host specified in the error. Review the list of Datastores and unmount the one that matches the datastore name shown in the error.
  
• Using the vSphere Web Client, connect directly to the ESXi host specified in the error. Review the list of Datastores the ESXi host lists, and unmount the one that matches the name shown in the error.
  

Advanced Troubleshooting

If the unmount process fails, or there is no datastore matching the name visible, you should consider restarting the management agents on the ESXi host listed in the error.

If the issue persists after restarting Management Agents, review KB4167 for details on removing latent entries from the ESXi host's Datastore cache.

Related  Veeam vPower NFS Service Articles:

• Troubleshooting vPower NFS Datastore Mounting Issues (Main Troubleshooting Article)
  
• Veeam vPower NFS Service fails to start
• How to test manually mounting NFS folder
• Unable to Mount VPower NFS Specified Key Name or Identifier Already Exists
• NFS share cannot be used
• Upgrade of Veeam Backup & Replication fails with Error 1327. Invalid Drive: