For the third time since I built this database, the
Autonumber field (a primary key) has created duplicates
upon itself.  

That is to say, after nothing significantly changed in the
Access application for many months at a time, one day, a
table just decides that I can't enter new records because
an autonumber is duplicated.  Location hasn't changed, has
not been compacted recently.  Given that Autonumber is a
field that cannot be updated (overwritten) by human touch,
so to say, why in the world does this happen?

Normally, I just create a replica of the original table
and append all of the records in the new table (with
Autonumber) and it's good to go.

Anyone have any idea why this keeps happening - or better
yet, how it can be prevented??  It would save me a lot of
time!

Thanks!