In the mod I worked on last night, trying to fix the issue in cell -1,1 suddenly almost all of my markers and about half of my major statics are missing in cells -2,3, and all adjacent to and including -2,6!
I think that deleting vanilla items and / or trying to clean dirty edits of navmesh with the ck cell view or data details method may be potentially very dangerous!

None of my remaining "dirty" edits are probably harmful. They may just be a consequence of finalizing neighboring cells. I am just going to have to live with the CTD area in cell -2,2 if efforts to clear it are going to potentially corrupt my mod. Until we get better editing tools...

I had to go back to a backup from the 18th for a copy that was not corrupted.
Thank God I back up at least every session and test every backup before I move it to a safe folder now!

Wow, that sounds incredibly frustrating. My condolences.

Here I was, thinking about starting a housing/new lands project.

could you hide the crash area under a large static?

I hear you shalani! I've not had much success in trying to clean up (or undo) edits either. But good for you keeping backups!!

Phinix, I wouldn't not do a mod, I would just take the lesson of keeping backups!! That's really the key.

And I sure wish we had safe tools. I know I could make my changes with TESSnip (I already tested) but I'm afraid of side-affects, so I don't keep the save.