This started after Hotfix 2, sadly Hotfix 3 didn't help. I can still only play with steam disabled. Nothing seems else seems to work
I tried deleting hotfixes, deleting mods, deleting mismatched files, reinstall, with and without verifying after each of all those, so yah I've tried nearly every permutation.
The only thing I can't do which makes me suspect this might be the issue is that in the userdata savegames folder there are safe files and folders that windows cannot find. I can navigate to them in windows, but If I try to copy, rename or delete these files/folders windows says the path cannot be found. I've tried using powershell with the same result, I tried using PrivaZer a dedicated delete and overwrite data program that fills the disk sector with garbage data to remove any sort of recovery operation. Even that could not find the location of these files.
Nothing besides closing Steam will let the game run.
For those of you that are crashing on startup, try navigating to your savegames folder and copying it to another location. After some time windows Popup Error might show "File cannot be found" "File is no longer at location." Maybe this is the issue, and if someone else can figure out a way to remove these files maybe we can cross off a potential fix.
For me at least this isn't a big deal, but for some who want Achievements, use the deluxe items, and or play with friends this issue is a huge problem.