On Windows, in the Failover Manager log, the message:
Invalid drive specification
does not always mean that the wrong drive was configured for the VMware Smart Assurance installation on the remote host. It can mean a permissions issue or other issue that prevents the Failover Manager from accessing the shared drive on the remote host.
The drive is shared with the correct permissions.
The Failover Manager service is configured to run as ".\Administrator".
Setting up Administrator service for PowerShell remoting (Windows only) on page 57 provides instructions about setting up the Failover Manager service.