What causes corruption?

In the majority of cases, an Access database becomes corrupt due to abnormal termination of the program. Typically, this is caused by either of the following:

• Power failure
• Crashed Server

Many of the repairs we do are the result of an electrical storm that caused a power failure on the Server. Less often is when the Server crashes.

But sometimes it is more difficult to diagnose why the database has become corrupted. One cause can be users running a query that takes some time to complete, thinking their PC is frozen and then using Ctrl+Alt+Delete to restart their machine. Consequently the database - particularly if it resides on the rebooting users machine - is terminated without closing down in the normal way. This can cause corruption, particularly if done on a frequent basis.

Also, if you have a networking problem where a Client workstation is intermittently breaking its connection with the Server, this can cause corruption.

There is no sure-fire way of preventing corruption. However, you can reduce the chances of data loss by doing the following:

• Regularly Compact and Repair your database using the utilities found under the Tools menu within MS Access itself.
• Create regular backups and check that the backup actually work! Quite often, we have had clients who thought their backups were working but they weren't. Get them tested periodically.
• Educate end users to never use Ctrl+Alt+Delete to close down their PC if Access appears to hang. If Access does freeze, check that it is not just taking a long time to run some code, a report or a query. Sometimes when data volume is high or the query is complex, it can take quite some time for the action to complete. This can mislead you into thinking it has frozen.
• If your database is frequently getting corrupted, check for possible dropped network connections.
• Consider upgrading the backend to SQL Server if you have large numbers of users, are suffering from frequent corruption problems or the data is mission critical. SQL Server is a more robust database and you are much less likely to suffer data loss. The downside is it is more difficult to program and is expensive.

Often, the "Repair Database" tool found under Tools, Database Utilities within Access itself can fix your database. Always try this first before contacting a data repair company as you can save yourself a good deal of money.

For more serious corruption where you cannot recover the data yourself, click here