Hi guys.

I am currently making a big house mod and there is a specific cell (main interior cell) in which everytime I go in game to test it, it crashes to desktop at a specific place in the cell. On occasion it wouldn't crash however most of the time it does. I thought it was because of a few items since they gave errors when loading up my mod in ck and so I removed them and still no luck. I then thought it was Auriel's Bow (Dawnguard) causing the CTD's since it has before but it wasn't. So finally I thought it was the waterfall that I resized to a smaller size because it was huge however it wasn't. I even changed my plugin to a master file but it still CTD's. So I'm stuck with my progress because I don't want my mod to CTD. Can anyone help me out on this issue please.

How well does your computer run Skyrim?

I ask because I ran into a similar (by the sounds of it) issue in my own mod. I am running many high resolution textures mods and basically pushing the capabilities of my machine to their limits with my build of Skyrim.
I was getting crashes because my cell had no other optimization (roombounds, portals, etc.), long line of sight, expensive lighting effects.

I followed http://www.creationkit.com/Bethesda_Tutorial_Optimization, and made sure that when using the # of lights debugging tool that no surfaces were coming up red. It pained me to alter my long line of sight as I liked it just fine how it was, but I need to cater to systems weak and powerful.

Doing all this has cleared up my CTD issues.

I would say my system runs skyrim pretty good. Core i5 2400, HD6850, 8GB 1600. And I have Skyrim HD Lite installed with a few other textures. I also run it @ max settings. However I never got any CTD's with all the mods I'm using, just when I equipped auriel's bow sometimes it would CTD. But thank you for your reply, I will try to follow the tutorial and see if there are results. I usually use a lot of lighting, the type without the red plus in the lighting (if you know what I mean) so they don't conflict with eachother. But I'll check how to do it with this tutorial. Thanks again!

Ok so I didn't optimizie my mod yet using the tutorial. I decided to jam abit of Skyrim and once again I got a CTD when I equipped Auriels Bow or a Crossbow. I searched the reason it happens on Google and it lead to the mod "Auto Unequip Arrows" being the culprit. Which funny enough solved my CTD's in my mod in that specific place in the cell! I am now relieved! But thanks for the help Antares, I'm still going to implement the optimizations however.

Good news all round. Also, I found the http://www.youtube.com/watch?v=5fZoIpKcJ6I&feature=relmfu video to be quite good. Very informative, plus it shows you a few tips and tricks.

Really weird that you were getting crashes that seem completely unrelated to the cause of the problem???

Nope I was wrong . It still CTD's, got so excited for nothing. Ok so I guess there is one thing left to do and that is to optimise the mod with the lighting and portals.

This is a dumb question, but are you using a clean save to test your mod? I mean, a save in which you've never had the mod loaded before, not even once. If you went into the game to test the mod, then later deleted something or changed something, that something may still be present in your savefile and now the game is trying to find it but it's no longer there. Wham, CTD.

It's one of the most common causes of crashes while modding. I once spent three days tearing my hair out trying to figure out why my mod kept crashing only to FINALLY realize that even though I'd only popped into the game for literally under a minute to test, somehow my autosaver chose that instant to do its thing. Since the autosaver doesn't change the filename of a save, just overwrites it, I didn't notice. And from then on a save that I thought was clean, actually contained a bunch of dirty edits from when I was fiddling with things that I later removed from the mod. Ooops.

I actually have never thought of that. Thank you ChaosPearl for informing me about this.

I have always just used the last save to test my mod and I am constantly testing it over and over on the same saves. And it does make sense because it does not always CTD but most of the time it does. So what I will do is load a save where I have never been to my mod, before it even existed, I will also try making a new save after visiting my mod. Will post an update on the results. Hold thumbs for me

UPDATE: So I loaded older saves where I never tested my mod, it gave me 1 CTD however like I said it does it at a specific place in my mod (a small waterfall green area that has collision) and when I was in that area of my mod, I heard moving sounds and realized it was the gold coins that I had put in the water in the waterfall/green area, I remember putting about 10 gold coins in the water around the place so I removed them in the CK. Loaded up Skyrim and kept on trying to get the CTD in my mod but nothing happened so then I put back my current saves that I have tested my mod on before and I still did not experience a CTD. I am not 100% sure if that solved the CTD but I haven't experienced anymore after the removal of the coins. Will post an update if I do.
UPDATE 2: Ok so it still gave me CTD's however I then loaded different saves again but with little progress in Skyrim and it has not CTD at all so far.

If you'd like, I'll PM you with my email address and you can send me your esp file. I'll see if it CTDs in my game. The fact that you aren't getting the crash every time in every save really makes me think the problem is a conflict somewhere or a missing reference in your game itself, not in the mod.

Another thing just occurred to me, you're not deleting any vanilla references or navmesh or anything like that are you? That would be a rather large no-no.