What's different about your saved configuration versus the default configuration? If restoring that makes the problem come back then it should be easy enough to track down.
My guess would be that your old/saved configuration shows additional columns which cause Opus (and the viewer plugins, video codecs, etc.) to open some of the files in your documents folder, and something is going wrong there.
If so then the FAQ I linked gives you the steps on how to track down what is causing the problem. Please follow them if you can and let us know what you find. If it's a problem in an Opus component then it can be fixed and if it's a problem in a 3rd party shell extension or video codec then we'll know to tell people to avoid/update it.