A series of unfortunate crashes

I second what Katherine stated earlier: nearly every time we encounter a case where Scrivener is crashing repeatedly, the problem is one of:

  • Firstly, the installation of Scrivener is damaged and just needs a simple reinstall. Sounds like you’ve already tried that, but I’m just listing it for the sake of completion.
  • Damaged temporary system and user level caches. After a big system update, I always run Onyx/Maintenance. Apple should be cleaning out temporary cache files when doing that, but it may not always do so in your user folder, I’ve found.
  • Old software/utilities are not properly updated, got broken in the upgrade, or are simply obsolete. Whatever the case may be, they can mess up native Mac software around them.
    • If Scrivener runs perfect fine in safe mode (yes, it will be too slow to use, but with regards to not crashing), but goes right back to crashing when you boot normally, then check to see if it runs fine in a test Mac account with factory settings in it. If that also crashes you probably have some deeper utility installed that is out of date. Stuff like Little Snitch and other security software are common culprits.
    • If the factory default account works fine, then it is almost always a utility you are using in the background. Clipboard helpers, text expansion tools, audio enhancements, etc. Just make sure all your software is up to date. Apple breaks all kinds of software with upgrades, you can’t update the OS without auditing your entire software list, especially the stuff you run on log-in.
    • More rarely these days there are matters of configuration that is causing instability, rather than running programs. You can determine if that is the case by holding down the Shift key directly after entering your login credentials, and keeping it held down until fully logged in. That stops all background software from running. If there is still instability, then something more passive in your Library folder is likely the cause, like a busted colour palette add-on, damaged font caches, etc.
  • Lastly, and less commonly: the upgraded system did not upgrade cleanly. Sometimes Onyx/Maintenance can help with that, but not always. Sometimes the system just needs a clean reinstall (honestly I rarely run Apple’s updates for that very reason, I’ve just never had good luck with them and find a clean install of the new version of macOS is almost fail-safe).