This unable to migrate error message suggests that the virtual machine cannot be migrated because one of the connected devices is not accessible on the destination host.
To workaround the issue, perform one of the following actions:
- If you are using an image file (ISO, FLP, etc.), 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.
Read also the following VMware knowledge base article to delve deeper.
Posted in: VMware vSphere