If ESPs have broken navmeshes that bug out NPC pathing after loading 2 different cells, how do we make our own NPC-compatible areas? The solution so far is to convert the ESP to ESM, but the problem with that is that you can't delete vanilla objects from the game (rock here, bush there, etc), since the Skyrim.esm will 'overwrite' your mod ESM and reload those objects in their default positions. So lets say I want to add a building to Riverwood and make it compatible with AI pathing. With the navmesh bug the NPCs will glitch out with the new or possibly even edited navmeshes inside or outside the building, but with the ESM fix the terrain changes and deleted objects that were done would become undone by the Skyrim.esm, as if the Skyrim.esm had load order priority.

So, is it our only option to make our new buildings/dungeons 'fit' with the current landscape/object design that Bethesda has by default? This is a huge pain due simply to clipping issues (it's hard to make a building level on an incline, etc). Please share your thoughts and workarounds for this.

Bump. Has anyone encountered this yet?

I personally haven't got that far yet. have you tested it and confirned the bug persists in Skyrim? Maybe they fixed it (crosses fingers)

Yes I have. Any user-created navmeshes will bug out if the player travels to the user-created navmesh area (whether it's exterior or interior), then loads 2 different cells, then returns to that user-created area. It's illustrated in this video that someone posted...
http://www.youtube.com/watch?v=RlNBVOcuW3M

Hello, I have no problem with the navmesh, all the custom exterior and interior areas I created works perfectly, npcs use the navmesh very well. I don't understand your problem.

Did you watch the video? Go to your areas, then fast travel somewhere else, then another place, then back to your area. Is the NPC pathing still okay? Patrols, daily activities, etc?

You can make bona fide ESMs with the Creation Kit which will not exhibit the problem. Here's how:

• Change file extension from ESP to ESM
  
• Open false flag ESM with editor and set as active, then load
  
• Save. You now have a bona fide ESM, extension and master flag

Using WryeSmash, you? can copy the ESM to esp if further editing is needed since the CK will not set a bona fide master as its active file.

NOTE: Before editing any Skyrim.ESM NavMesh, assign it an EditorID (its FormID works well) from within the Cell View window. This will reduce the likelihood of the editor deleting the original and replacing it with a new, isolated NavMesh native to your plugin which other plugins' NAVMs, NAVIs, and DOOR REFRs cannot and will not reference as they'll be looking for the original Skyrim.ESM NAVMs.

NOTE: The ESM flag being ticked is the important part. An .esp file will work with its ESM flag ticked (masterupdated) even if its extension is not altered.