STUCK AT 66%? - Updated: 04-11-19
IMPORTANT: May require several attempts.
Game version: Digital Copy*
*Works with game pass confirmed.
Solution credit: jetCrownDPrince
WILL NOT require reinstalling the game.
1. Go to Halo 5 Hub (NOT your service record). To do this, hit the guide button on controller. Scroll down to "Halo 5" then hit the three line button on your controller. Select "Official Club".
2. From the Hub, select "Progress" tab at the top. Go to "Stats". Note your matchmaking victories. Now your service record, check to see that you have won at least once on all three maps (storm, arc, spec 7) for both firefight and regular warzone.
3. Delete profile from console. Do not recover it, you will do that later.
4. Clear blu ray persistent storage 5 times. (Located in Xbox settings)
5. Hard reset Xbox (hold down console power button for 10 seconds til it turns off). Don't turn back on.
6. Unplug power cord. Make sure the power brick light is completely off.
7. Wait ten minutes. Have a snack, I did. Recommended.
8. Hook it all up, power on via controller.
9. Start up halo 5. Remember your profile? It will ask you which profile. Click "add" and recover your profile. Sign in while on the halo 5 main menu.
10. Wait to be fully sync up. Super important. Without being fully synced, your efforts will not count. A way to tell if this failed, start searching matchmaking but you get booted back to the main menu. If this happens you are not synced. Start over.
11. Now start heroic fire fight. Win! Yep, try to win the first or second one. Doesn't matter the map.
12. After win, check halo 5 Hub and make sure the victories I pointed out earlier increased. If NOT, you are not synced. Revert back to step 3.
13. If it went up, you're good to go! Jump into regular warzone and do not leave queue. Play every match and do not quit. Me, I would run around in the back of the map and watch YouTube til I found one of the three maps since I didn't know which ones I needed.
Important note: I pick regular over firefight because of better map rotation. This achievement can be unlocked in either.
14. When you find the maps needed, win/lose keep track on paper. Wait to watch your character leave on a pelican. Stay in queue, load up next match and give it a few minutes before checking the hub again so that data has time to upload and be accuate if counted. If you win and victories doesn't change. Restart back to step 3. If they do change but no achievement then continue onward til it pops.
15. Achievement has popped. Freedom!
I popped mine losing on Escape from ARC. It's rough but it's better than doing 60 hours + guessing when it will pop. Total time spent trying to figure this out/ warzone games/ all other sultions and reinstalling digital copy which I did not need to do: 44 hours. Hope this solution saves you time. Good luck!
IMPORTANT NOTE: I helped people pop this for over a year, however, as of 7-01-18, I will not take anymore requests due to how busy I have become. I do wish you all luck.
Important: post updated 04-11-19