Dragon Age Origins crashing after defeating demon inside Connor

I had this issue as well and was having no luck with the listed fixes and I did not want to try the code, then by sheer luck I found it the way to start it. As soon as Sophia starts walking talk to a party member. For some reason if you're in the conversation screen with them she doesn't lock up and continues to the start location.reloaded 3 times to double check and it worked all 3. ( I can't say if this works for Avernus didn't try)