Ah, forgot about that option. Updated.
Those crash logs don’t give us a function name to look for in the native code, which makes it hard to know what in Java is the culprit. I don’t understand why you can’t reproduce the problem with the test case, and my experience with reporting bugs against Java is that they will put no effort into pursuing problems they can’t reproduce—even when you point out precisely what’s wrong in the code and give them a patch to fix it. (Here is an example where I’ve done that, with no success.)
I’m reasonably certain that you have something unusual on your system that’s reported by the Windows file dialog code to Java and then mishandled. I expect that you would not have the problem anymore if you reinstalled Windows; short of that, I don’t know what else to recommend.
I have one more suggestion: Install a stand-alone JDK and try running the “Other” bundle of Vassal with that. See if you can reproduce the problem that way.
Here is a current 64-bit x86 Windows JDK to install, and this is the platform-agnostic Vassal bundle for 3.7.2.
I have been trying, but no luck reproducing with those. I can never predict when it will happen. Just that it will.
Well it is no help, but I have confirmed it is somewhat time based. I had the new VASSAL for a few months with no issues as usual, but then (I don’t know maybe after adding so many mods or something) it goes from working great, to be being able to load log files. Someday I will just redo windows, but wish I could peg this one down. And I wonder why it is just me, but it has been just me for a couple years now.
Since the cause is likely to be something corrupt on your machine, I’m not surprised at all that it’s happening only to you. Nobody else’s machine is corrupt in this way.
Have you ever tried running Vassal from a different user account than your normal one? If it works from another user account but not from your normal one, that would suggest the corrupt file or files are in your user directory.