If you see it freeze again, please make some manual snapshots and send them to us: Manually generating process snapshots
The DOpus.Minidumps snapshots would be the only automatic ones, so if they aren't there then there won't be any other information to diagnose.
Freezes and crashes like that are sometimes caused by particular files, and may in turn be triggering bugs in shell extensions or video codecs etc. something else has installed, or could be bugs in Opus itself. Manually generated snapshots can often reveal which component (and sometimes which file) is causing the problem, but failing that, try to think of any unusual action or folder you performed or visited just before the problem and see if doing the same again can recreate it. That is often enough to track down the cause.