I just completed the mission Fire in the sky, why did I not receive the achievement for doing this?
Answer
If you lose your connection to battle.net for more than a minute or so, Achievements are automatically disabled, and do not get re-enabled for the duration of the mission, even if you subsequently reconnect.
There is a pop-up on-screen that mentions this, but it’s easily missed, especially if you are in the middle of directing a pitched fight.
If you have a save near the end of the mission, you can try reloading it, though there’s no in-game way to check whether or not achievements have been disabled for the current map. A more provable solution would be to replay the mission from the start. Even if your internet is fine and dandy, it’s not impossible Blizzard has been experiencing some launch-day network hiccups.
Another alternative (that I don’t think applies to your case) is that you used some of the single-player cheat codes, which will also permanently disable achievements for the current campaign.
Attribution
Source : Link , Question Author : Blem , Answer Author : Community
