Trying a fresh install, and wondering if the installation path is being weird. Found this:
http://steamcommunity.com/app/208580/discussions/0/541907867749517999/
I've been installing the EE.exe file straight to the KOTOR2 folder (steamapps>common>Knights of the old Republic 2), never had any problems in the past.
Well, I got M4-78 (Steam) working properly, tried installing EE again, still no luck. Tried installing before and after removing the mirachoke line, still no luck.
Well, despite using Steam M4-78, EE didn't install. I then unsubscribed from M4-78, ran TSLRCM only (also using the Steam version of that mod), and the installer told me 'TSLRCM was not installed properly' and didn't go through. So...
New bug. Playing steam RCM with non-steam M4-78. Go to Korriban. Find the interrogation room. Bag is there with datapad. In active quests, instead of anything about Vash or her padawan, it's just default "Vash was killed by assassins."