Find out mapped network drive logins

If you have shared drives in a multi-domain environment and need to know what each drive was logged on as, this is the command to find out:

WMIC NETUSE GET Name,UserName

or

WMIC NETUSE LIST /FORMAT:LIST

or

Another way to see this is to look on the machine that is hosting the shares.
Look in Computer Management -> Shared Files -> Open Files.

This will list the user account that is being used.