Can't continue College of Winterhold quest, Mirabelle won't give next stage

I am at level 56 and erased all my previous saves, so going back is not an option. At the College of Winterhold I started the main quest line early on, at level 12.

I went up to 'Hitting the Books' and stopped for a while, then went back at level 40ish and did 'Good Intentions'. But after the Archmage died in 'Containment', Mirabelle won't give me the rest of the quest. She was outside instead of inside when she told me to look for him and I can't do the rest of the main quest chain for it. I have done every other guild but the college and refuse to start over.

I am playing on the Xbox 360.

Solution 1:

This is a common bug for the Containment quest.

The easiest solution would be to reload the save, but that isn't possible in your case.
The alternate solution would be to complete all other active College of Winterhold quests and reapproach Mirabelle.
Since you don't have any other College of Winterhold quests and you don't have any old saves to return to, it appears this quest is glitched and subsequently locked for you. While lamentable, this is a Bethesda game and a valuable lesson on maintaining multiple saves.

If you were playing on PC or had modded your Xbox 360 to accept console commands, you could fix the quest by inputting:

setstage MG07 0: Start the quest after Containment (The Staff of Magnus)

player.additem 000a34f8 1: Quest item from Containment (Torc of Labyrinthian)

player.additem 000f1b33 1: Quest reward from Containment (Savos Aren's Amulet)