I made a thread about this several months ago, and have been struggling (with what I thought was a simple task) with it on and off since then. Now I'm finally ready to throw in the towel so I'm posting in the hopes someone more talented than me can help me get this to work.

So I'm trying to turn one of the npcs from http://www.tesnexus.com/downloads/file.php?id=25604 into the default new player face, as per the CS wiki walkthrough http://cs.elderscrolls.com/constwiki/index.php/How_To_Make_an_NPC_Playable

The NPC is an Abriael Imperial, so I'm loading the necessary masters to get the npc face in the CS to copy it. (Oblivion.esm, CM partners.esm, Cm partners.esp, Abriael human.esp, and Abriael companions 3.esp). I've then been following the steps in the walkthrough to turn the "player" npc into a female Abriael Imperial, and then applying the npc face. I then save it to a new .esp.

When I run wrye and boss, then rebuild and try to start a new game, it CTDs at the end of the new game load screen (before the opening cutscene).

If I try to load up my new .esp and the masters in the CS, it gives me errors along the lines of "can't find hair for NPC 'player'", and "can't find race for NPC 'Player"". If I continue thru the errors, there is no 'player' npc in the CS, so I assume this is the problem or at least related (this occurs even if I give it a stock game hair and eyes instead of the right ones).

I've exhausted my very limited knowledge of the CS at this point. I can post my load order if its needed.

What am I doing wrong, and what do I need to do to make this happen? (thanks in advance)

Do you just want the face or the entire character? Face import is easy, NPC import (+ converting to PC) is tricky.

Well if its put on another race it doesn't look the same, so I guess I want to import the npc and make it playable. I'm open to other things however.

Does this mod use a custom hair? And did you select it for the player? It may be that the hair style you want for the player is not actually playable, so the game will not let the player use it. If that is so you'll need to open the 'hair' window and check the playable box under the custom hair.

The npc just uses Corean hair 19, and unless I'm sorely mistaken that's definitely playable. However, I've tried just changing the "player" to Abrial Imperial and switching it to female (leaving default hair etc), and it still gives me the "unable to find race (05000ED3) on owner object 'player' " error when I load it all back up with my new .esp. Obviously when I select yes to keep loading, there is no longer a "player" npc.

Haven't bothered to try it in game because I think I'd just end up needing a new keyboard.

Anyone know how to make this happen, or can point me in the right direction?

You just pointed in the right direction yourself... seems like your own esp doesn't have this race. Hairs shouldn't be a problem, because if you'll lack this hair it'll change them automatically on default one (probably blindfold) and it won't cause any error, the same with eyes.
So you simply don't have this race, and even if you add it, it'll be totally other race.
You can merge that plugin where you got him and your plugin.
Or you can change his race to vanilla race (for example Imperial) and see if his face will change much or not.

Ah, very interesting. Thank you very much. I activated all the appropriate masters, including the custom race esp, and figured that was all it needed to recognize the race. I should have known it wouldn't be that simple.

I've asked around and someone pointed me to a program that (with a little work and a few crashes) allowed me to solve my problem. Regardless, I'll fiddle with the CS and see if I can do as you suggested just to learn more.

Thanks!