After installing the mod everything works fine, but when you load a map in the maps folder - minecraft completely hangs without Crush.

Sorry for the molestation, but as soon as you fix this? Once again I apologize.

I tested this with just RebornCore and HardCoreMap Reset, on the recommended version of forge in mulitmc, so I will need to take a better look when I get a chance.

ah ok, thanks. That should allow me to reproduce the issue.

Two things.

1. I am also experiencing this bug.
2. But only when the "thumbail" issue is set in the map's info.json
   Without the thumbnail option this bug does not happen.
   The rest of this post is the exact default auto-generated info.json (with a "stand-in" for the mc ign though).
   {
   "author" : "MC-Name-Here",}

It generates the second line containing the author option with 2 leading spaces.
I forgot about html format correction removing redundent spaces while typing it.