Performance Drop After "Compact and Repair" in Access

After doing some modifications to an MS Access accounting system used by a client, the users were complaining that the application had become excruciatingly slow.

After spending some time going through my code, server event logs, and application error logs, I came up empty handed. It was only after reverting back to a backup and retracing my steps that I found the problem started after a "compact and repair" was done on the back-end. Logic seemed to state that doing a compact and repair would boost performance. But in life, all is not as it seems.

This discussion seems to shed some light on the issue. It might have been caused by indexes being reset, or queries having to be recompiled. I still haven't figured out the exact reason for it. But reverting back to the "uncompacted" and "unrepaired" version of the back-end helped to bring performance back to the way it was. So I guess a moral of the story would be "don't fix it if it's not broken."