I have a fairly complex (approx 200,000 lines of C++ code) application that has decided to crash, although it crashes a little differently on a couple of different systems. The trick is that it doesn't crash or trap out in debugger. It only crashes when the application .EXE is run independently (either the debug EXE or the release EXE - both behave the same way). When it crashes in the debug EXE, and I get it to start debugging, the call stack is buried down into the windows/MFC part of things, and isn't reflecting any of my code. Perhaps I'm seeing a stack corruption of some sort, but I'm just not sure at the moment. My question is more general - it's about tools and techniques. I'm an old programmer (C and assembly language days), and a relative newcomer (couple/few years) to C++ and Visual Studio (2003 for this projecT). Are there tricks or techniques anyone's had success with in tracking down crashing issues when you cannot make the software crash in a debugger session? Stuff like permission issues, for example? The only thing I've thought of is to start plugging in debug/status messages to a logfile, but that's a long, hard way to go. Been there, done that. Any better suggestions? Am I missing some tools that would help? Is VS 2008 better for this kind of thing? Thanks for any guidance. Some very smart people here (you know who you are!). cheers.