Haven't tried Explorer since I have Opus 9 as my default service. Since the crash occurs intermittently, I'd have to test it a while before I can answer you. It's surprising that no one has raised this issue earlier (I checked FAQ), so I wonder what's different in my system.
I'll try using Windows Explorer and get back to you.
I reported this in an email to GP soft but they weren't able to reproduce the bug. The only solution I found was to turn the previewing off for .doc extensions.