I've just found the courage to try to convert a very complex database from filemaker 6 to filemaker 9. The original was 10 years in development, and has a great many complex scripts. (As I'm an amateur, some of you might see the programming as awkward) In any case, I have managed to make more than 60 notices of: "This record cannot be modified in this window because it is already being modified in a different window." go away, but two remain in the stubborn path of my executing scripts. Is there any way to find out which window and which record is being blocks, and which window is trying to do the other modifications? I've added "commit" lines all over the place. Particularly frustrating, is a subscript that only pastes a bit of text from the clipboard into a field and that is called 5 times during the larger script. For the first three times, it works properly, for the last two, I get this error message. Any suggestions are most welcome. I don't have much hair left.

I also went through this process some two years ago - I think it took me a year to debug.

The biggest ones I faced was creating related records between FILES using GLOBAL fields to pass the key info from parent to child - but I was often not releasing the parent record.

There is no easy way, but as you have FMP Advanced then run the script debugger and trace it step by step.

Incidentally I abandoned copy/paste techniques when script parameters and $variables arrived in FMP - often the copy buffer gets corrupted.