Missing achievement?

[DoctorXOR]

So the other day I got the "Old School" achievement for completing 10 retro warp zones...and realized that I don't have the "Living in the Past" achievement for completing 5 retro warp zones -__- I tried verifying the integrity of the game cache, but nothing happened. Any ideas on how to fix it? (also, don't know if it matters, but I play SMB on a Mac)

[MilleniumLuigi]

Well, it's a commonly known achievement glitch with steam, unfortunatley, you must have been offline when you got 5, thus it did not register oin steam. No way of fixing it unless you start the game afresh. (would not reccomend doing that, it's just an achievement, lol.)

[Day]

I read in another thread, to be sure, that you keep your progress (expationally with warp zones), play another level at the end of gaming

[DoctorXOR]

Yeah, I was offline when I got 5, was wondering if there was a manual override or something. Nbd.