sg,

The stored procedure is only for SQL Server logins, not Windows logins.  It
is used to synchronize names to update the user SID to match a login SID,
since these can differ across machines for SQL Server logins.

For Windows logins, the SIDs do not change across machines since they are
defined by the domain.

Therefore, if you have an orphaned user 'domain\user' one question is, does
the server have a login with the same name and SID?  If not (and it should
not or you would not have a problem) can you add the login to the server.
If the SIDs match, the user should automatically be reconnected.

RLF