I was going to say that fixing the nav mesh should be the first thing. A few other things to try testing: Loading only this problem mod in the CK and see if you get any popup errors. Load problem mod and generate new navmesh data. Test. Load all most you are using in the CK, if possible, you will need to enable option in the CK INI for loading multi masters. Then make a test patch with the problem area(s).I should mention that if the mod changes buildings in the area you will need to generate new navmeshes for this mod. unless you like you companions and NPCs running into walls or getting stuck. navmeshes are easy to redo, it take a few minutes. I have to say, that mod author was either lazy or forgot. Let him know about that issue so he can fix it.