Joe's advice is correct but incomplete. Some simple rules apply.
1. Always backup your work. A regular backup operation is not merely a good idea. It should be a mandatory part of any operation that is considered crucial to your business operation. But remember that this doesn't stop ANYTHING from being corrupted. It just limits your losses.
2. In any design, always close what you open. Always delete what you create as soon as you no longer need it. And never create what you don't need in the first place.
3. Murphy's Law says that Anything that can go wrong WILL go wrong. But nobody remembers the second half of that law... (Bet most of the readers of the forum didn't know there WAS a second half.) Part 2: ".. so design your process so that nothing CAN go wrong."
In practical terms, this means that if someone tries to close your database while something critical is active, disallow it from closing. It usually means a lot of work, such as building a "trapping" form and making everyone work from the trap. E.g. what is called a "switchboard" form. You never see the database windows for tables, queries, etc. Just the switchboard. And the switchboard, being a form, can execute code to block an exit/close if the conditions aren't right.
4. One of the best ways to prevent corruption is to undertake an extensive program of user education with a bunch of thou-shalt-not statements. Like
Thou shalt not turn off thy computer without first logging off.
Thou shalt not log off thy computer without first closing Access.
Thou shalt not close Access without first closing open forms and reports.
Thou shalt not let thumb-fingered idiots run your forms and reports.
Thou shalt not let thy network engineer get ANY SLEEP AT ALL if thy network is still flaky.
