I followed Olava the Feeble into the inn in Whiterun. Oddly enough, she wasnt inside despite seeing her wlak inside. So I left and Uthgerd runs up and attacks me. Won't accept my yield. I killed her and a courier comes andgives me inheritance money, since I beat her up in a fist fight once, ages ago.

What happened?

Just say Uthgerd to wait, and then enter Olava's Feeble house. So just load a previous save and try that.

If that doesn't work, commit a minor crime in Whiterun in front of a guard and then clear your bounty using the usual methods. This should clear up her hostility.

And lastly: Select her in the console, use setAV Aggression 0, then disable her, and enable her again.