Load order keeps CTDing at main menu—where do I even start debugging?

[RiftenWanderer]

Just reinstalled a bunch of mods after a couple years away and now the game won't even load past the splash screen. I'm on PC with MO2, and I've got maybe 80 mods installed (mostly texture / weather / QoL stuff, nothing crazy). I know the usual suspects are USSEP and SKSE compatibility, but I have no idea how to actually find which mod is causing the crash without disabling everything one by one for an hour. Is there a smarter way to narrow it down, or am I just gonna have to bite the bullet and test half my load order at a time?

 

[WhiterunModder]

Binary bisection is your friend here. Disable half your load order, test. If it crashes, the problem's in that half—disable half of that again. If it doesn't crash, re-enable that half and disable the other half instead. Keep splitting until you isolate the culprit. Way faster than going one-by-one.

That said, before you even do that: make sure SKSE is actually loading. Open the console in-game and type "getskseversion"—if nothing prints, SKSE didn't load and that's your crash right there. Also double-check that USSEP is actually enabled and that you don't have multiple versions of it floating around in MO2 (I've seen people accidentally have two USSEP installs and wonder why everything's broken).

If SKSE loads fine and USSEP is clean, then yeah, binary search your mods. Start by disabling all the weather / ENB stuff first though—that's a common culprit for main menu crashes specifically, way more than QoL mods usually are. If it loads with those off, you've already narrowed it down a ton.