Try these guides, as applicable, for the best suggestions on tracking down the cause of the crash (usually a shell extension or video codec). They come from the "Other Troubleshooting" section of the Opus FAQs.
The problem is almost certainly a 3rd party component crashing inside of Opus, which is largely outside our control. It's the component that will need to be fixed (by its authors) or blocked/removed (by you, if you choose), but first you have to narrow things down to which component is triggering the problem.
The best way to start is to see if you still get problems when pointing Opus at an empty directory. If you don't, then one of the files in the directory you were poiinting at was probably triggering the problem, and something you have installed for working with that type of file is probably the root cause.