>Where is the NODEFAULT keyword in the MSDN help? Using Index tab to search for the word, it points me to the right keyword, but pressing ENTER, it points me to DEFINE CLASS.

You're quite right, VFP Help has never covered NoDefault properly, it should have its own command, as you say, like a compliment of DoDefault.

>The problem:
>Using VFP6 SP4, NODEFAULT in QueryUnload doesn't behave properly. We don't have this problem in SP3.

Something else is wrong, Jess, NoDEfault still works fine for me. Try creating a small form with Nodefault in the Queryunload and run it under SP4. You will note exact same behavior as SP3 and earlier, the form cannot be closed, am I right?

I suspect your problem is somewhere else - I've seen threads where people are having other SP4 variable/function interpretation problems.