I know what you're thinking: missing master. I guess it's possible, but I've followed the STEP guide using Mod Organizer, LOOT (including metadata tags, shows no errors or warnings), TES5Edit (cleaned master files and other ITMs when marked to do so), Wrye Bash, ENBoost... I'm at a loss right now.
It should be mentioned that I played the game successfully with no issues for 7 hours yesterday with the same mod setup and everything. The CTD began after changing skyrim.ini and skyrimprefs.ini files, as well as enb ini files. I changed ENB settings first (using Shift+Enter in-game), and the game was still running fine after that.
I initially followed all of STEPs ini setting choices, but was still noticing flickering (I have a 144 Hz monitor, but FPS limit is on, so not because of that), so altered some LOD settings to settings suggested by Michael of GamerPoets (did not set anything higher than he suggested), and you can check my system specs -- they should be able to handle nearly anything. I double checked spelling and the letter in front (b, f, i, etc.).
Logically, I reset both skyrim.ini and skyrimpref.ini files (yes, in Mod Organizer, not just data folder), thinking it should fix the problem. It did not.
Mod list via Mod Organizer (this is unchanged from when the game WAS working, other than adding MemoryBlocksLog after the CTD issue started):
The "nothing" of a log I get from Documents/Games/Skyrim/Logs/Script Papyrus Log:
From SKSE.log:
I deactivated all mods -- same CTD. I ran through Steam (avoiding SKSE, and I have no workshop mods) -- same issue. I'm guessing something was accidentally deleted.
If there's anything else I need to post for more info, please let me know and I will do so ASAP.
Thanks for your time.