halo 3 achievement problem?

[Alex]

i beat the storm on normal for the first time, and i didnt get an achievement. anyone know what went wrong and/or how to fix it?
i started from where i saved in the middle, maybe thats it

 

[ZAck H]

No idea if it was your first time. Maybe you stopped half way through and saved it, then started up again. Play it through one more time and see if it works, then let me know.

 

[Wiz of Halo]

I believe in order to get the normal achievement you must complete the whole game on normal. If your talking about the single achievement, then you must start from the beginning of the level. If the problem persists, try contacting Microsoft or Bungie