Devastating Achievement not unlocking

Games Halo: The Master Chief Collection
1

Last night I completed Halo on Legendary on co-op and the achievement is not unlocking. My service record for Halo Waypoint shows that on co-op I should have the achievement for I completed the game in two hours and fifty three minutes. What’s up with this achievement?

2

Having the same issue myself, my time is well below the 3 hour mark.

3

Any update on this. I beat the game on legendary solo less than 3 hours and achievement did not unlock?

4

Beat Halo 4 on legendary solo and it didn’t give me Legend of 117 or Lone Wolf Legend. I went to career to see which mission I didn’t do it sent me to do the prologue I did it anyway watched the cutscene and then went to Dawn then I went to the menu to see if it did anything. Nope. Still saying I need to do prologue so I came here and it said I need to beat Requiem on legendary so I did it’s still saying I need to beat Requiem. Any ideas on how to fix this? I’m hoping it won’t do this for 1, 2, 3, and ODST.

5

I, too, am having this issue. Here are my completion times, on Legendary:
Sierra 117: 19:46
Crow’s Nest: 16:37
Tsavo Highway: 11:05
The Storm: 13:01
Floodgate: 7:35
The Ark: 22:01
The Covenant: 26:46
Cortana: 17:06
Halo: 17:50
All Chapters: ~2:50:00
Can anyone advise? Is 343i aware of this issue?
Please help,
Exultraviolence

6

Aha! Loading the Prologue and Epilogue solo did nothing for me, seeing as how I completed this run co-op. I plugged in a spare controller, and signed in a Silver account, watched the Prologue, and the achievement popped. If you’re having difficulty unlocking this achievement, and your circumstances are similar to mine, I’d highly recommend trying something of this nature, with either a Silver account, or an online buddy.

7

Lots of bugs in MCC - I am unable to unlock the campaign difficulty achievements because it says I’m missing the prologue as well but it won’t count it as played when I watch the cinematic which is all the prologue is. Also, lots of ammo boxes throughout the campaign do not function, don’t refill ammo. The achievement bugs are the most frustrating though.