“I get told, `You already have a connection to the Domain....' or `Cannot join domain, the credentials supplied conflict with an existing set...' when creating a Machine Trust Account.”

This happens if you try to create a Machine Trust Account from the machine itself and already have a connection (e.g., mapped drive) to a share (or IPC$) on the Samba PDC. The following command will remove all network drive connections:

C:\> 

net use * /d

This will break all network connections.

Further, if the machine is already a “member of a workgroup” that is the same name as the domain you are joining (bad idea), you will get this message. Change the workgroup name to something else it does not matter what reboot, and try again.