Just wondering why there is an identical MultiMarkdown folder (1.1MB) in both the application’s MacOS and Resources folders. Is it possible that two identical sets of information inside the application might account for the odd crash?

I’d be surprised if that caused any crashing. The MMD stuff doesn’t even do anything until a bit after you actually click “Export”, and then Scrivener is just essentially running a command line and waiting for it to finish. I’m sure it is hard-coded to one of these, and the other might as well not even exist.