Can any one help? I'm a level 58 Breton, and I cannot procede in either "missing in action" or "retrieval", as whenever I try to enter the locations my xbox locks up, can anyone give me an hint as how I can "find a way to release Therold from Thalmar custody" with out having to enter the keep?

try clear the xbox system cache + try to wait 30 in-game days

worked for me all the times except in blackreach, where the game freezes everytime i use candlelight spell