For the last few years, every few months I find that Ztree will crash on starting while trying to load the default temp.zlog file, or when trying to save the same file mid-session.

I've never been able to figure out any pattern to it, except that if Ztree shows an impossibly high number of logged files in the "DISK Statistics" panel at any time then it's likely ZTree will crash the next time it's started with an existing temp.zlog file, or when saving same. One other indicator that a possible crash is imminent is if the zlog file and/or Ztree's memory usage is unusually large for the number of logged files.

If I knew the format of the zlog file then I figure I might be able to throw together a "repair" utility, if only as exercise for my brain.