I can't investigate Mirmulmir after killin him, I have Dragonborn and Dawnguard installed, started a new game. I loaded a gamesave from this new game but not workin. I have the 3 latest unofficial patches installed for patch 1.9. Have this mods installed (load order)

AOM.esm

Dragonborn.esm

Dawnguard.esm

Unofficial Dragonborn patch.esp

Unofficial Dawnguard patch.esp

Unofficial Skyrim patch.esp

AOM.esp

Stone of Barenziah mod (from Steam workshop)

Rich merchants.esp

Prisoner rags for female.esp

Train 99 skills per level (from Steam workshop)

Sweet & sixy lingerie.esp

Newmiller Casual Bikini UNP2.esp

Newmiller Shoes UNP.esp

Thanks for all help,

EDIT: No problems when I was playin with patch 1.8 and 1.8 unofficial patches.