[dba-SQLServer] Can't find the principal

I have databases that I created on one machine.  When I move the database
file to a different machine I get a "can't find the principal" error when
trying to mount the database on the new machine.  The reason appears to be
that the owner is the user under which the database was created on the old
system.

How do i get around this?

John W. Colby
Colby Consulting
www.ColbyConsulting.com