And did the message box get displayed?
In two years of daily debugging in XLv.X, I haven't seen this, so
I'm at a bit of a disadvantage.
Do you have selections, or does your code depend on which sheet is
active? That might create a difference between when you step through
it and when it runs on its own (i.e., if you're starting out with a
different sheet/range active).
Have you tried other breakpoints?
Removing and reinstalling XL is a Windows-type solution that is
rarely effective with MacXL. To do it right, you have to run the
Remove Office application that comes in the Value Pack folder of the
installation CD. The reload, reapply all the updaters, and repair
permissions. Did you do that? More effective might be to
remove/trash Preferenced from the ~:Library
references:Microsoft
folder, specifically the Excel Settings (10) file and perhaps the
Microsoft Office Settings (10) and the Office Registration Cache X
files.
If it's something you can send me, I'd be willing to take a look at
it on my machine. Stuff it and attach it to an email from the
address you posted from. Document where it's not breaking.
If not, perhaps post the code and let us know where it's not
stopping.