>>Would it be possible to see your code? I have from 25 to 250 users on VFP applications I have created and we do not have these problems.
>
>Yes, thanks for your help, I have a milion headaches every day from that behaviour.
>
>the code are in methods of baseform class on wich are based all forms
>the tables are optimistic table buffer

My first thought on reading this was that you're clobbering your key/index values. I didn't see enough in your code to verify this one way or the other.