Take a look at an article at http://www.craigberntson.com/Articles/kb005.htm

>Hello,
>
>I have an older foxpro 2.6 application that I wrote that has work fine for years. Lately however every 2 weeks the software gets an "internal consistancy error". I end up having to delete on of the main databases index files and recreate it from scratch. This seems to fix the problem every time. I have gone through my code a number of times, nothing has changes from when the app was working fine. I have even recreated the exe file a couple of times.
>I am no where near foxpros limit for records or file size.
>
>Does anybody know what happening, or have any ideas how to stop it from happening?
>
>Rich Imbruglio