Tuesday, September 28, 2010

Help! My Database is Corrupted, and I Can't Repair!

As a follow up to my recent series on compacting databases, I thought I should say a word about the repairing part of Compact and Repair.

As a file-based database system, Access is more susceptible to corruption than a server-based database like SQL Server.  However, Access databases are not quite as fragile as many believe. The most common causes are external to Access: PC hardware problems, network problems, users shutting down Access, or killing the Access process when it is accessing the disk.  A few are internal: use of the Name Autocorrect feature, multiple users using the same file, or memo fields.  These last do not cause corruption, but corruption is more likely when used.

In my experience, most of the time a corrupt database can be fixed by Compact and Repair.  I personally have had only one database that was not.  That one happened when I lost network connection while I was compacting the database.

But although it doesn't happen often, Access databases can be corrupted beyond repair, or at least beyond the ability of Compact and Repair to fix.  In some cases, you've no alternative but to resort to your backup.  (You DO back up your database regularly, don't you?)  But there are things you can try before you have to resort to that.

The following links are some of the standard references for recovering a corrupt database.

Jerry Whittle's Fix Corrupt Access Database v4.5
Allen Browne's Corruption Tips
Tony Toew's Corrupt Microsoft Access MDBs FAQ


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