How do I reset the autonumber field back to Zero?

In your table design, delete the autonumber field and then put a new autonumber field in. This will automatically start from zero and fill in the subsequent numbers.

What if i want the same field name with the autonumber reset back to zero?

Set the field type from auto number to just number, save the database, then change the field type back to auto number and save. This resets the counter.

Also, if there is no data in the table at the time, running Compact Database will reset it too.

I have a table where I need it to start over each month. I delete all of the records, compact the database, and then import into the table.

BL
hth