it is really so, Auto-increment fields in MS Access are always incremental, even if records are deleted, database compacted, etc.
The proposed number can be reset deleting the auto-increment field, perform the copy of the table and then adding the auto-increment field again.
It is possible to duplicate numbers in autoincremet field quite easy, but normally applications don't work this way.
Access remembers last inserted value in autoincrement field and uses it for calculating next value. You cannot insert particular value into autoincrement field using table designer or recordset in VBA, but it's possible if you use INSERT SQL statement. So, if autoincrement field has no unique index, you can insert any value. Also if you insert value less than maximum existing number, Access will generate duplicates automatically.
So I would not recommend rely on unique autoincrement numbers without unique index.
INSERT SQL can be used for resetting numeration without dropping field/table, just run query like this in query builder or using VBA:
INSERT INTO Table1 ( id ) SELECT 1;
This is table with autoincrement field ID I just created:
Asked in February 2016Viewed 3,054 timesVoted 7Answered 3 times