Deactivate, but how? :) Anyway, here's what I have done: (I write here in detail so everyone can see what they'll face)
1. Copied complete DCS folder and Saved games folder on an external.
2. Installed a fresh W8.1.
3. Downloaded and installed core DCS 2.0
4. Copied back DCS folder and saved games folder to where they needed to be.
5. Launched DCS. It logged in auto (that must be for I copied saved games folder)
6. DCS told me that I had no terrains (here's where I got furious).
7. Then DCS asked me to install every module I had. I chose none but one (A-10C).
8. DCS quit, updater started and asked me what to do with unfinished dl files it found.
9. I told to keep them and then it started to download it all over again.
Please let me know where I have done wrong, and I will see if I can correct it, since everything's fresh here.
Many thanks!
Edit: I also ran cmd dcs_updater repair. No change.