You can't resolve the Database Owner (dbo) in this fashion. You'll have to you sp_changedbowner.

-Mike

>Hi,
>
>I have a little problem this morning when I trying to restore a database on another server.
>
>First of all, I have a database called 'bdX' and the dbo user mapped with Login1.
>
>I backed up and restored the database. When I ran this command:
>
>exec sp_change_users_login 'Update_One', 'dbo', 'Login1'
>
>I got this message...
>
>Server: Msg 15287, Level 16, State 1, Procedure sp_change_users_login, Line 38
>Terminating this procedure. 'dbo' is a forbidden value for the login name parameter in this procedure.
>
>Why ? and What can I do ? is it an important message to solve...
>
>Thank in advance.
>
>Dave Sonier
>Technologies Nter