Board Thread:Bug Reports/@comment-28813058-20170212122610/@comment-25330335-20170212190937

Rayn Turammarth wrote: Get MultiMC ;)

I find that this issue tends to be caused by Optifine or Fastcraft, try removing them. If that doesn't fix it restart Minecraft until works again.

Fastcraft should not do this. I'd really like to know exactly why optifine causes this problem, since it seems pretty sporadic. However, this post is the best example of what to do in this situation.

The launcher should have nothing to do with the issue you're experiencing, although if you hate the new launcher, and don't want to go to the trouble of downgrading from the old one, give MultiMC a shot.

On a more or less useless note, the image above shows where map.png is supposed to go (white space), and where the mod is supposed to substitute blue in for water (brown space). Optifine must be preventing the mod from putting those together to create the map.