I have had a database in production for over 2 years now and just had problem with October. When pulling up this report I get an "overflow" error. The query of the underlying report works fine. I've narrowed the problem to one field on the report. The control is in a group footer and just is Sum([FieldName]). If I remove it it works fine but I really need this field. I've tried changing the datatype which was originally single to double, to long integer, to decimal. Nothing works!!! It won't work on any other machine and this has worked for 2 yrs but any month prior still works.

The report stores information about fields when they are built. You may need to rebuild the control with the problem or force Access to re-register the report's recordsource by deleting it and then adding it back.

That doesnot work. Tried deleting the recordsource and field, saved the report, then open it back up and recreated the field and added back the recordsource.

Is there any "corrupt" data in Octobers records

I though maybe was the case but I deleted all October data then did a compact and repair then reimported it. And did I mention the underlying query works. This is so friggin weird and there is not much info on it anywhere.

Have you tried deleting Octobers records and entering some dummy data for that month, as opposed to your actual data