I did not touch any of the doors or exterior cells, I havnt "deleted" any of the original references just disabled some statics and lights... but Im not very experienced with this, are there any sort of common mistakes noobs like me make that cause this kind of issue?
Edit: Well I did some reading around and saw mention of an ESP being too big causing this kind of crash(mine was up to 196kb), and bookshelves causing it. So I deleted the shelves and got the filesize down to 143kb and no more crash. That svcks, but at least it wasnt the navmeshing. I dont suppose theres a solution to this other than to delete things?