VMotion fails with the compatibility error: Currently connected device uses backing which is not accessible

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• Performing a VMotion in vCenterServer fails.
• You see the error:
  
  Unable to migrate from <source server> to <destination server>: Currently connected device'<device>'uses backing '<device>', which is not accessible.

Environment

VMware vSphere ESXi 6.0

Cause

This issue occurs when one of the connected devices cannot be accessed on the destination host.

The possible devices that can show this message when connected are:

• CD ROM Drive
• Floppy Drive
• Serial Port
• Parallel Port

Resolution

To work around this issue, use one of these options:

• If you are using an image file (ISO, FLP, and so on), ensure that it is accessible from all ESX Servers. Store the files on a datastore that is shared between all ESX Servers that will participate in the VMotion of the virtual machine.
• Disconnect the device from the virtual machine before performing the migration.