Hello,
I used to play alot of Halo Reach on xbox, gained 55 achievements.
Now I’ve bought Halo: The Master Chief Collection and downloaded everything, but the achievements won’t sync.
I’ve waited for 2 days and played alot of different gamemodes, I am enabled to unlock achievements all together, It’s just the sync problems, it looks like i’ve never touched the game ever. Don’t have any armor or stats.
Also tried to re-install the game without succes.
Reach achievements don’t sync.
The MCC has it’s own, new achievements. You won’t get any from the old, original game on 360.
Did you get your achievements on MCC or the original game?
Oh, that makes alot of sence. I got it on the Original game.
After some digging I found this article wich confirmed your answer and told me more about it:
Realy sucks that you can’t transfer it, oh well 
Thank you!
Hello there fellow Spartans,
I have an Issue with the game.
I bought it on steam and wanna know why the game doesnt give me any achievments or playtime ingame? (stats)
i tried reinstalling, rellogging to xbox. nothing works.
i would love to hunt down all 700 achievments.
PLS HELP
Thank you in advance
Seanter96 [JD]