Lost campaign progress

Games Other Halo
1

So I was going for the achievement to finish all missions solo on Legendary difficulty. I started right from the prologue and went right through and finished the campaign, but I noticed that upon completion of the final mission the achievement didn’t pop up and I didn’t get to see the (minor) Legendary ending.

I also noticed via waypoint that the 5 terminals I had previously collected had vanished (the ones in the 2nd, 3rd, 4th, 5th and 8th missions).

When I returned to the menu after watching the epilogue, I found that the game thinks that I have not even completed the first 3 missions at all (and they were locked until I watched the prologue, claiming ‘you must complete the previous mission to continue’), although prior to my Legendary playthrough I had already finished the campaign on Heroic.

I now have all the campaign commendations for finishing the missions on Legendary, but no achievement.
Any assistance would be greatly appreciated.

2

This is generally caused by a profile data corruption bug.

Xbox LIVE’s servers keep a backup of users’ profile data. I think that if you delete and recover your profile, then you may be able to get an old (pre-data-loss) backup with your Campaign progress intact.

3

> This is generally caused by a profile data corruption bug.
>
> Xbox LIVE’s servers keep a backup of users’ profile data. I think that if you delete and recover your profile, then you may be able to get an old (pre-data-loss) backup with your Campaign progress intact.

That sounds quite risky…
I’ve already played the 1st mission on Legendary over again. I just have to do the 2nd and 3rd and I should in theory get the achievement.
But thanks anyway.
I’ve had the same issue before with Halo Anniversary. My brother and I were going through the campaign on Legendary and upon finishing it realized that the game claims we missed a mission, and had to replay it.