I had just entered the White Marches region for the first time and was trying to save the game. After I clicked "save" the game crashed (I had issues previously when trying to save, but nothing other than it taking a moment to load, I thought that was just because I have quite a few save files). I haven't been able to start it ever since (no black screen or anything, just a window informing me the game has crashed).

 

I'd previously played the game for over 30 hours without any major issues. I've since uninstalled (I tried to wipe every file related to the game I had) and reinstalled the game, but that doesn't seem to have changed anything.

output_log.txt

DxDiag.txt

Solved!

Turns out my Direct-X decided to spontaneously corrupt some of its files. I still have no idea why, but after reinstalling everything's running smoothly again.