Most custom applications will have an Autoexec macro that initializes the environment when a user opens the database. Sometimes it becomes necessary to prevent the execution of this macro in the course of debugging. To prevent the Autoexec macro from running hold the shift key down when opening the database. With use, the internal structure of a database can become fragmented, leading to wasted disk space which can result in poor performance. Additionally, databases may become corrupted.
Corruption typically occurs when users reboot workstations, power goes out, disk drives go bad.
The usual practice is to Repair the database first and then Compact it. Reclaims unused space created by object and record deletions. Resets counter fields so the next value allocated will be one more than the last undeleted counter record. Regenerates the table statistics used in the Query optimization process. These statistics can become out of date over time, typically due to transactions that were rolled back or when the database was not properly closed.