This is a new feature of Access 2000 and beyond. You need to work in an
off-line copy so that people can still work in the database while you are
developing. To do this, you must also split the database into a Back-End
database (BE) which holds only the tables, and a Front-End database (FE)
which holds everything else. After you make changes to the FE, you can
simply copy it over the old FE and the users will get the changes. If you
try to do this without splitting the database, you will over-write all the
data that your users have input that were not in your copy.