I dunno if anyone else has run into this yet or not but I managed to make YMS break the game. I dunno how it happened but I had an NPC follower attend my stall. It was not a Vanilla npc, it was Gorr from 3DNPC. After I told him to watch it and then came back to retrieve him I could not longer interact with my market stall at all and upon further play I realized that all of the NPCs could no longer give me items and that any scripting that effect the player was now broken; the scripting system would crash during the dialog after the commands were issued.
I confirmed it was caused by this mod by loading to a save before the glitch happened and disabling YMS. Did not change any of my other mods. Went to the place I have been testing fixes at and was able to get the burial ashes from Thodagir (or whatever his name is from the Dead Man's Drink in Falkreath).
I do have another 178 mods installed so it may be that YMS was conflicting with one of them in some way that caused this to happen.
Found a Game Breaking Glitch (2 comments)
I confirmed it was caused by this mod by loading to a save before the glitch happened and disabling YMS. Did not change any of my other mods. Went to the place I have been testing fixes at and was able to get the burial ashes from Thodagir (or whatever his name is from the Dead Man's Drink in Falkreath).
I do have another 178 mods installed so it may be that YMS was conflicting with one of them in some way that caused this to happen.
Surely this couldn't have broken your entire game...That sounds hard to believe.
I know I'm probably late af, but try that, and use a save before it got messed up. No doubt that one will be okay