TES Construction Set has a feature that enables you to combine loaded plugins - take two mods and moosh them together to make a bigger one. But is there an automatic way to split them back apart? Currently, the best I've come up with is to use a combination of tools such as Enchanted Editor, TES Plugin Conflict Detector, MWEdit, and whatnot to do the job manually. It's very onerous when what you're trying to extract is an old version of Tamriel Rebuilt! Thanks all.

Just as a minor aside , which version of TR were you trying to retrieve? If you can't generate a tool necessary it's possible someone has it archived.

Oh, sorry stillcrazy. No, I don't need to preserve the old TR if that's what you're asking. I'm taking it out to make way for the newest version. The two have too many differences to simply combine the new version over top of the old one. I can't just make a new combo from scratch either because this is part of my MW Amalgamated project - dozens of big mods all smooshed into one giant plugin. The old TR has to come out while preserving the rest. The TR references are as per original, but I've made too many changes to the other components of this amalgamation to simply start over. I'm hoping for something like:

plugin 1: A+B+C+D

plugin 2: A

'MagnificentTool' compares plugin 1 vs plugin 2 then provides for:

plugin 1 - plugin 2 =

plugin 3: B+C+D

is A old TR version in your possess?

Yep, though that might not be the last mod to need such treatment. I think Rise of House Telvanni might have undergone significant changes since I began this project, so it might need a look too.

Try loading plugin 1 in CS with A (probably A would be both TR_Data.esm + TR_Mainland.esm) as master esm, then save 1, this should remove most duplicated A objects from 1 (if not, clean with TESTool).
Then remove A as master for 1 using Mash, load 1 in CS, save. This should remove most references to A objects from 1
clean 1 with tes3cmd and testool, there should not remain much of A in 1
[EDIT]make backup of 1 before starting