I'm sorry to post this here because this question is all over the Internet but I've been completely unable to solve this via searches.
I'm running Steam installed Morrowind and Oblivion. I followed the instructions to the letter and installed Morroblivion via Wrye Bash.
I installed OBSE as instructed. But when I start a new game I'm in the prison cell and the Morroblivion popup says OBSE is not installed.
I've tried to solve this for 2 days now but I just don't know what else I can do. I've tried switching off UAC for Windows 10, enabling and disabling Steam overlay, starting Steam in administrator mode (but then Oblivion launcher crashes to desktop).
Any ideas?

How did you install OBSE? Are
How did you install OBSE? Are you launching the game with the OBSE exe?