Have you had any luck restoring the VSC to any kind of useful state? Does the new behavior seem to be accumulating visited stars from a blank slate, or does the visited stars filter now apply only to systems visited in the current play session?
Yeah, I was able to rebuild it with my travel history (getting it back to the state it would have been in anyway). But here's what it took... There are account-specific IDs in it, so I had to write a script to copy those from a freshly created VSC. I also made sure to put in the correct timestamps and visit counts, based on my travel history from EDSM. And this works.
Based on poking around with this myself, and coordinating with a few others who were also poking at it, it appears that it is culling the file based on how many systems you've been to, according to your codex exploration history, but with some margin of error. I suppose it would be possible to make VSC files specific to an area that you want to explore, but it may not be practical. For one thing it would be limited in size to the number of systems you've visited, so veteran explorers would have a huge advantage over newer accounts. The other check it seems to be doing is to just delete the file if the account IDs are wrong, so any program that is generating the file for you would have to know what those are. The simplest solution is to copy them from a freshly created VSC file.
Beyond that, I'm not sure if they're checking the visit counts + timestamps on each entry in the file. If they are, it might be a simple sanity check (no zeroes, for instance). Since I recreated mine with reasonably correct numbers for these, I haven't tested it.
All of this is in a binary format, using the system 64-bit IDs, with specific header and footer data, and visitation counts and timestamp of last visit for each system. Making a generic tool for this might now be considered a violation of terms of service, plus the tool would have to be smart about your account data. So... yeah.
