Created this account to join in on the conversation like so many others. First of all thank everyone so much for all your information.
This bug has made it impossible for me to play for the past four days at least but I�m convinced my saves must have been corrupted much earlier (probably at least two weeks ago). I just never noticed it because I didn�t need to leave the Lower City.
I�ve read every single post in this thread and my problem is very similar but there�s a few things specific to my problem that I haven�t read here before.
I first encountered the bug after finishing the Iron Throne quest. I finished it normally but when I was back in the Lower City and saved (!) the game crashed immediately. No loading, just immediate crash after pressing save. I repeated this several times until I understood that the saving is the problem. My game doesn�t crash when switching locations/maps like it does for everyone else, it�s ALWAYS when saving (both manual save and quicksave) after leaving a location/map. But aside from that I have the exact same experience with the bug.
I went back into a quicksave during the Iron Throne fight and noticed one of Mizora�s spiders that was already dead still as an icon among the active enemies. (Probably one of the dead enemies whose HP haven�t dropped >0.) I decided to ignore the quest for now and went into an old save.
Next I did the Free Oscar quest and when I noticed a ghost enemy dying in a weird visual way I saved and the game crashed immediately again. I started googling and found reddit posts and this thread and started my hunt for undead enemies.
I have NOT done the quests Iron Throne, Steelwatcher Foundry, House of Hope, House of Grief, Cazador, Ansur, basically any big quests that take long or require me to leave the Lower City map, that�s probably why I hadn�t noticed the bug earlier. I also never had to travel out of Lower City because I had finished any quests aside from Dribbles, Ansur and Gortash.
I have done the Hag quest but I saved every possessed NPC and the girl and only killed Ethel so none of those NPCs are bugged. I went back to any scene of fights I could remember to look for �undead� enemies and actually discovered that Sarevok was dead and still had 23 HP left. I killed him but this didn�t fix my bug. I can�t find any other undead corpses in the Lower City or Rivington.
I haven�t killed any steel watchers aside from the two next to the boat close to the Umberlee Temple (they attacked me without warning when I stepped onto the boat) but their HP are 0 so they are not bugged.
The only other out of the ordinary thing I remember noticing before learning about the bug was at Felogyr�s Fireworks. One of the enemies, the chemist, glitched while dying. He was dead and his HP were 0 but his model hovered over his dead body on the ground. I went back but everybody there is definitely dead-dead and mostly despawned. Only the Flaming Fists in the area are weirdly aggressive. They accuse me of trespassing even when I�m OUTSIDE on the streets next to the Fireworks shop.
When I travel from Lower City to Rivington and back to the Lower City I do NOT experience the crash immediately like everyone else, I have to SAVE but then the game crashes immediatley. That�s the only big difference I found. I can fast-travel within Lower City and save after that just fine without crashes as long as I don�t leave the map. I can also travel back to Rivington and save there without crashes. The crashes only happen 100% when re-entering Lower City and then saving. (And as I mentioned I generally can�t save after leaving the Lower City map such as for Iron Throne quest. Same would probably happen with House of Hope quest but I haven�t tried yet. Also the game will apparently crash randomly while saving during/after fights such as the Oscar quest so I�m not hopeful that I can do Steel Watch Foundry, Cazador etc.)
At this point the game is completely bugged and I can�t finish it because I can�t kill Gortash and save afterwards. I could possibly beat the game by finishing it without saving and just fighting Gortash and the end boss. But the game�s auto-saving before big events will probably crash my game anyways and I really don�t want to finish my run without having done the companions quests.
I have tested all of my saves from the past five days but haven�t yet found one that isn�t bugged.
Btw this is my second run. I finished my first run on October 1. and never encountered this bug. I played both runs with mods but of course we all know this bug has nothing to do with mods at this point. I play on PC, Steam, with Gforce. Haven�t sent any reports to Larian yet aside from the crash reporter ones that open automatically after the game crashes. I�d love to support this whole situation but from what I learned in this thread I can�t send my files to Larian if I use Gforce.