>Any explanation ?
>
>I'm using VFP 6.0 SP3.
>
>Suddenly SET STEP ON courses an C000005 error when the program gets to this line in my code??

I'd only use Nick's suggestion of deleting FOXUSER.DBF as a last resort, but that does work. Try just opening the debugger (without trying to debug code) and clear all your breakpoints. Works for me.