Today I was planning to submit to the App Store the current build of SwiftoDo, which I have been testing without incident for about three weeks. Unfortunately, out of nowhere, it started crashing on launch late this morning. Fortunately, I never finished submitting this build to the App Store for review, so it will never reach users. It does mean, however, that I have to debug a tricky treading-related crash before I can release the cool new feature I have been working on.