I've been building lately a modlist for my next playthough. Having been burned out too many times before for the inevitable issues we know will assault anyone trying to get a modded Oblivion to work out as we hope, this time I've been very careful, adding few mods at time and testing throughfully before adding the next bunch. I've been saving modded Oblivion installations as backup every time I reached a threehold I was happy with. I have now an apparently satisfying working fully modded Oblivion with all my "must" ticked on.

However if I try to add another mod that requires its .esp (or .esm) to be active, independently of what mod is, the game will crash to desktop in a matter of seconds in any exterior cell. It seems that if I keep the active plugins under 230, it'll work fine, but going above that, CTD comes knocking.

I was under the assumption that the limit of active plugins for Oblivion were 255. I know also that there's a limit for how many bsa the engine can handle before it fails, but I though that the mark was somewhere about the 300 mark. I haven't count them, but I am sure I am nowhere close to the 70 bsa needed to reach the 300 limit. What am I missing here?

Well, the failure limit is how many esps, esms and bsas are in your data folder - not even active in your load order. Thats' something you can check.

Other than that, we can help better if you post your mod list.

If you have Wrye Bash, you can turn on Auto-Ghosting, which will rename un-activated ESPs and ESms to *.ghost so that they won't count towards the 255 limit.

Here's an interesting discussion on the (bugged engine) consequences of having too many plugins in the Data folder. A few pages in, it appears that this phenomenon is why the ghosting feature was added.

http://www.gamesas.com/topic/941296-bugz-oblivionexe-filedirectory-thrashing

Shademe's plugin http://www.nexusmods.com/oblivion/mods/44108/?also fixes this bug.

I knew it, I knew it was Trifle. I spent quite an hour looking at the Trifle plugin description, and then searching other shademe's mods, and just couldn't see that feature listed. Today, after Turija's comment above, I see it plain as day.

I thought it was Nitpick in Skyrim that fixed that feature for that game, but Trifle does it for Oblivion. Thanks Turija for confirming what I vaguely remembered.