I had 10 corrupt vanilla files
A few months ago I wrote an article entitled 3 reasons why your game is broken. The number 1 reason, is something changed in your game. This could be almost anything but most often it is a misbehaved script or the result of a poorly written OIV installer wreaking havoc.
When Code 16 broke reverted games, including mine, I made quite a few changes - lots of experimentation - secure in the knowledge I had backups. Finally I got my game up and running thanks to the bypass mod and it's working great. That's why I was surprised when this happened.
I have GTA 5 SP but I also have my own FiveM servers, not for RP, only for SP and private (localhost). When I started FiveM yesterday after a few weeks or longer of not having used it, I got a fatal error from the client saying that one of the vanilla dlc patches had been modified and a brilliant suggestion to use a Mods folder when I modify files. Wonderful. This wasn't something broken with FiveM, it was telling me my vanilla SP was screwed up.
Except I had never modified that particular rpf, I always use a Mods folder, and I had not installed any mods that changed that particular rpf. Solution? Well that's easy, we just restore the rpf from backup, right? Nope, the backup failed as well.
So what next? Panic and blame SH5? Or OpenIV? Reinstall 20 times? None of the above. I did a verify integrity and much to my surprise I had not one, but ten files that had to be reacquired (9 if we don't count my gta5.exe from 2372). I had a perfectly stable game with 9 corrupt or modified vanilla files when it should only have been the 2372.
Moral of the story? This isn't the best example because it involves both SP and FiveM, but it just shows that our games may unknowingly have corrupt files that could impact us down the road - with other SP mods for example. It also confirms that error messages, from SP or FiveM or often wrong, useless, or just part of the problem. Restoring the rpf didn't fix anything. Reacquiring it along with 8 other files is what fixed this issue.