Is COMPACT ON CLOSE perhaps turned on? I'm not sure how it works (since I would never even consider using it), but perhaps it closes the database, compacts it and reopens it for some housekeeping? Doesn't make much sense, but you should consider COMPACT ON CLOSE, anyway, because:
it is useless: any Access app should be split, and users will only ever open the front end directly. Since the front end has no data stored in it, there is no need to ever compact it (if it bloats, replace it with a new one, or redesign it properly, so that it doesn't bloat).
it is dangerous: under certain circumstances, a Jet database can be in a corrupt state, but still open, with all the data still accessible. But in some small percentage of cases, a compact of a database in that state will cause some of the data that was still accessible to be lost during a compact (I've seen it happen when a PK index got corrupted). So, since you can't cancel it, you are in danger of losing data that would otherwise remain accessible without a compact.
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David W. Fenton
David Fenton Associates