vRanger backup or replication fails with Error Message: One or more disks from virtual machine is already mounted (4042693)

vRanger backup or replication fails with Error Message: One or more disks from virtual machine is already mounted

Sample replication error:

• vRanger replication fails with Error Message: One or more disks from virtual machine VMname is already mounted to virtual appliance. You must unmount these disks before attempting to replicate the virtual machine.

Sample backup error:

• One or more disks from virtual machine VMname is already mounted to virtual appliance. You must unmount these disks before attempting to backup the virtual machine.
• One or more disks from virtual machine VMname is already mounted to the vRanger virtual machine. You must unmount these disks before attempting to backup the virtual machine.

This can happen when a hot-add replication is abruptly cut off.  It can be caused by the vRanger machine rebooting, a service restart, and the VA being powered off mid-replication, to name a few.

Please follow these steps to correct the issue.

1. Let's confirm if the backup is processed by the vRanger server or by a virtual appliance. In the vRanger UI go to My Jobs. | Scheduled Jobs | Select the backup job that failed | Click Edit | In the wizard go to Transport Selection and on the bottom half confirm if the job runs on Machine Transport (the vRanger server) or on Virtual Appliances (VA).  
2. On vSphere Client, go to the VA listed in the error message or the vRanger server, depending on the transport used.
3. Select the vRanger server or VA, go to Edit Setting, or right-click and edit setting and look for the disk of VM that is failing to backup or replicate by reviewing their file names. This is generally the 3rd disk or 4th disk
4. Select the disk to be removed and click Remove (In the Web client it looks like a button with an ‘x’ to the right side, it might be transparent and visible only when the cursor is near). When prompted make sure the "remove from virtual machine" option is selected. DO NOT delete from disk.
5. Once the disk is removed, you must also remove the snapshot from the VM to which the disk belongs. If the snapshot does not appear in Snapshot Manager, close Snapshot Manager, manually create a new snapshot, then open Snapshot Manager and select Delete All.
6. Once removed re-run backup or replication job.

    In this example the source side VA was rebooted during the replication job.
    The taks log shows the following output:
    "Error Message: One or more disks from virtual machine <server_name> is already mounted to virtual appliance <virtual_applaince>.  You must unmount these disks before attempting to replicate the virtual machine."
    You can see from the screen shot, hard disk 3 is the source disk of the VM being protected in this job.