I've sent a private message with a link to a test version.
Please download that, and inside the zip you should find a new dopus.exe
This will only work with 12.13, so make sure you are (still) on that version.
Close down Opus (kill it using Task Manager if the lister is locked up and File > Exit Directory Opus won't work).
Using File Explorer, copy the new dopus.exe over the old one, but don't run it yet.
Grab DebugView from Microsoft and run it. (DebugView doesn't need to be installed, just unzip and run the exe from anywhere.)
Now run Opus. You should see some output in DebugView.
You'll probably need to resize the columns in DebugView to see it properly. They are very narrow by default.
If the crash/freeze still happens, please let us know what DebugView displays with either a screenshot or a text copy of the log (via the File menu in DebugView). I'm also interested in knowing if it keeps rapidly outputting information non-stop, or if it only shows a few things at a time and is generally calm.
The test version has a couple of changes which could potentially fix things on their own, if we're lucky, but the debug output is the main purpose of it.
I'm also uploading some old installers in case we need to narrow down exactly which version the problem started in, but that will take some time.
Many thanks for your help tracking this down.