Diagnosing non-reproduceable bugs?

Question

I've got a very basic, but terribly important and potentially impossible question: how does one go about diagnosing a bug you can't reproduce?

Twice now, I've gotten emails from people asking about app-crashing bugs that I can't reproduce. Non-modified iPhones, current software, tried reinstalling and hard resets, etc. It crashes every time for them, and it works perfectly for me, (not to mention it got approved for the App Store in the first place so I'm clearly not the only one). I had always understood that the consistency of the devices was one of Apple's big selling points for developers, but that also makes it hard to pinpoint what's different about their device from mine...

So, aside from "just keep testing," is there a trick-of-the-trade among programmers for this sort of thing? Some function of the iPhone simulator that lets you test not just different screen sizes but different hardware configurations, etc? Or am I just out of luck, and stuck telling my customer "sorry, it works for me"?

Can anyone share their experiences or suggestions about this?

Answer 1

You should probably start by installing a crash reporting tool like Crashlytics. This may give you the clues you need or at least help you narrow down where to put additional crash logging.