crazydrop, I have the same problem, I would very much like to hear the "long" version of your problem and solution. I too cannot open any parts regardless of format .sldprt, .step, .iges originating anywhere, my own files, downloaded files, files from a colleague. and a series for updates, uninstall/reinstall, etc. have been zero help. Very frustrating. I'm glad to hear you found a solution, and hopefully it applies to me too. Thanks!