Hopefully you've split your application into a front-end (containing the
queries, forms, reports, macros and modules), linked to a back-end
(containing the tables). You'll need to make the changes to the back-end.
Yes my system is split and I need to add additional fields to the backend.
The problem is each user has a copy and will have lots of data, how can I
add a field/ alter fields in this situation?