Seems to be a common issue but I completed the Legend achievement on the 24/7 but I haven’t unlocked the armor set. Tried the hard reset, reinstalling MCC, starting another level on Legendary then quitting, and customising my spartan then joining an MP game
Probably not the right forum but I’ve stopped recieving unlocked nameplates and avatars on the Master Chief collection aswell
GT is SuetySalmon thanks in advance
Annoyingly I’ve got the same problem. For months I’ve been redirecting people to the different Helioskrill posts to try the solutions, then I thought I would give it a go myself. I completed MCC legendary when it came out, but it didn’t always register properly, so recently I redid those missions, and finally got the legendary acheivement.
Of course, Helioskrill didn’t unlock! I tried all ths solutions that I’ve been directing everyone else to do, but they didn’t work for me at all! So yeah, I’m in the exact same boat, and I’ve been trying all the solutions for weeks and still nothing has happened. I’m just going to hope I get lucky with REQ packs I guess. Do let me know if you manage to get it though!
Start a mission on legendary on MCC and then go back to Halo 5
that has worked for everyone ive suggested it to
> 2533274888753908;3:
> Start a mission on legendary on MCC and then go back to Halo 5
>
> that has worked for everyone ive suggested it to
No luck, tried it twice. Thanks though
> 2533274866464944;4:
> > 2533274888753908;3:
> > Start a mission on legendary on MCC and then go back to Halo 5
> >
> > that has worked for everyone ive suggested it to
>
> No luck, tried it twice. Thanks though
Same here, started Halo 4 Midnight and it didn’t seem to unlock it. When you did this, what mission did you use (you never know, it could be a mission which triggers it)?
Update, fired up MCC for the first time in weeks and played some games of Slayer (lag city btw such a let down) and my unlocks for MCC finally registered and Helioskrill unlocked
> 2533274884447055;5:
> > 2533274866464944;4:
> > > 2533274888753908;3:
> > > Start a mission on legendary on MCC and then go back to Halo 5
> > >
> > > that has worked for everyone ive suggested it to
> >
> > No luck, tried it twice. Thanks though
>
> Same here, started Halo 4 Midnight and it didn’t seem to unlock it. When you did this, what mission did you use (you never know, it could be a mission which triggers it)?
I used gravemind on Halo 2 
I’m not sure if Halo 2 missions are the only ones that work but they may