So I've made a couple of NPC, and place them into a cell I made. Should be one of the most basic actions...

But somehow the GECK manages to forget NPC-references when I load the ESP and save it again.

1. I create a dummy cell, just a room with four corners, create a new NPC, and place him in the cell.
2. I save the ESP, reload ESP => NPC is still there.
3. Saving again, reload => NPC is gone, (Base object Count 0)

What gives? It's similar to the UseMultibounds issue, but only affects NPCs, and only those defined in the ESP; NPCs from the ESM stay put. When I place several new NPCs, some of them stay where there are, next time another bunch is gone; the earlier I placed them, the more likely they will stick around.

Is there another weird ini setting that needs to be changed?

Edit:
Examining the ESP with Tesnip, the reference is still there after saving the esp the second time, when I save it the third time (i.e. the NPC was gone in GECK) the reference is gone.

Edit2:
Using Tesnip to change a perfectly save and persistent NPC reference to link to another NPCobject's FormID will cause that reference to be gone after the next save/reload/save/reload. Perhaps an issue with a certain bunch of FormIDs?

Okay, seems like I found the culprit.

For future reference:

My ESP actually had two GRUP (NPC_) entries: the NPCs in the first group were perfectly save, the ones in the second group were the ones the Geck kept forgetting. After merging the two groups, everything seems to be fine.

I have no idea what caused this. Until now I never even used "File/Data/Details" on that ESP, let alone opened it in another editor. Also, during my tests, some NPCs from the rogue group somehow managed to slip into the proper group.

Well, at least now I know where to look if it happens again, and can actually continue working on my mod...

There are several threads at newvegasnexus which also complain about this behavior, like http://www.thenexusforums.com/index.php?/topic/282817-objects-disappearing-in-geck-after-saving. Using tesnip (or the more modern fnvedit) to merge the records as you describe is the solution. But, nobody has been able to pinpoint *how* the duplicate records get there. If it is a geck bug, or some kind of user error, it would be helpful to make it easier for the next guy to recognize he is having this problem. Can you make it happen again? It would be useful to know.

Seems like every time I create a new NPC by changing the EditorID of an NPC from the ESM, the new NPC is put into a second NPC_ group that is located at the end of the ESP. Copies of ESP-NPCs are put in the proper group.

Those misplaced entries are only part of the problem, though. I don't know about FO3-Geck, but the Morrowind and Oblivon TESCS were much more tolerant to such dupe-entries, even when they were made by editing the ESP with 3rd party programs. I assume the GECK doesn't wait until the ESP is fully loaded before it evaluates the cells, and thus ignores all references to entries that come after the cell group.

Ah-ha. So the steps are:

1. I have an esm and an esp loaded in geck
2. I copy-modify an NPC from the esm
3. Geck creates an invalid database which is, a second NPC_ group containing the copy-modified NPC
4. I save the esp, and everything seems fine
5. I load geck, and the NPC is gone, because the second NPC_ group is not read.
6. I take the original esp from step 3, bring it up in fnvedit or similar, and the second record is automatically merged
7. Now my mod works again.

This is very helpful to know, and I will cross-post it to the other thread.

With ESM I meant Fallout.esm, there is still more to it though, sometimes the NPCs are sorted in correctly, sometimes not. The same applies to statics, or weapons, basically all placable objects you created, no matter whether you use a new model or just made an exact copy of an object.

The ESP is evaluated step by step, for everything to be loaded properly cells have to come after placeable objects like NPCs, creatures, statics or items.

When I save my mod, sometimes placed weapons are missing after reload, sometimes NPCs, sometimes new statics, sometimes all of them, and infrequently everything is fine. The problem isn't just caused by the dupe entries: the CELL group itself is placed at random positions in the ESP, and chances are good that it is above some object groups, which will cause all cells to forget all references to those objects, next time you load the ESP.

As a routine-action before loading my mod in the GECK, I started to open it in TESnip first, and manually move the CELL group to the bottom of the file (Cut/Paste)

Odd... cause I duplicated an NPC, and in my ESP he never went disappearing on me, I work from my own ESM now, but still.... its odd how I never ran in to this.

Update:

After working for three weeks on my mod, and having to use TESnip to move the CELL group to its proper place everytime I saved the ESP, I made a cleanup and removed the remainders of the small casino I built to get back into TES / FO modding before starting "serious work".

All I did was removing the obsolete new chips and casino object from my WIP, and now the Cell group was properly put to the bottom of the ESP everytime I checked for the last five days. (CELL is still above MESG, but that won't cause any problems)

Seems like the new CHIP and CSNO entries (or any other entries new in FO:NV) are the culprits, might be an oversight in the saving routine.

That is interesting. The person who reported this problem at newvegasnexus was working with weapon mods like laser sights, which unless I am mistaken, is also a new feature in FNV. Not that there is much chance of gamesas fixing it, but at least modders can be aware of the problem.

Hmmm, I wonder if that's why I kept getting missing NPC's? I've literally lost a week's worth of work redoing stuff I already had done because my peeps disappeared. It's been really, really frustrating. My mod has a new casino and chips as well.

Easy to check: FNVEdit won't help here, but TESsnip is included in FOMM's tools menu.

While FNVEdit lists the entries alphabetically, TESsnip uses the ESP-File's original order.

All groups with placeable objects need to be listed before GRUP (CELL) otherwise they will be removed from the cell when the ESP is loaded.
To fix the ESP just Edit/cut the GRUP (CELL) entry, then select the file name at the top of the list and use Edit/paste to move the cells to the bottom.