When you use the net use command, and don't specify the disk share, you will experience this behavior if the DOS-based computer only uses the NetBIOS Extended User Interface (NetBEUI) protocol. For example, if you type net use \\ComputerName\ShareName, the DOS-based computer returns ???? as the UNC service name, resulting in an invalid device type error.

To workaround this behavior, specify a disk share, as in either of the following examples:

net use * \\ComputerName\ShareName

net use <DriveLetter:> \\ComputerName\ShareName