Question: When the endpoint is intalled and running as a windows service, I cannot access the mapped drives from the endpoint. (rbClient does not see mapped drives)
If you are running the endpoint in service mode, check the permissions on the mapped drive and make sure that the local SYSTEM account has full rights to it. If it doesn't, then the endpoint software will not see this drive since it runs as the SYSTEM account when installed as a service.
To check that it is installed as a service, you can either right click the Remote Backup system tray icon and see that it says Uninstall Service Mode. You can also verify this in Task Manager's process tab and see that it is running as the user SYSTEM.
If the endpoint can be run in Application mode, then that will solve the problem easily. In Application mode, the client will see any mapped drives, and this is the default. Use this if at all possible.