Xbox LIVE Gamerscore & Achievement Leader Stallion83. World's First Ever 1,000,000 Gamerscore achieved on 3.13.14.....and still climbing.
But that's just it, you don't have all of the achievements. If you did then that achievement wouldn't be able to unlock because it would already be unlocked. Since you don't have it, it can't unlock because you don't have it.
But the achievement refers to not having the achievements in the sense that all achievements in the game besides that one itself are the actual achievements unless you count all the achievements as an achievement.
I know what it refers to. I just think that this is perhaps the mistake they made. If they thought of it as more of a Platinum trophy then perhaps it would be unlockable.
This is a known glitch in the game, which i am sure is one that will never be fixed as Disney now have much larger games on their plate to contend with