Modpack World Holes

[Lehmyare]

My two friends and I were playing on our world when our power went out, a few hours later we were able to get back on. After a while of playing, we realized that a world hole cut the back part of our reactor off. We thought that logging off and back into the world would fix the problem, but in the long run it made it worse. After the first log off, there was about fifty creepers, in a group, standing outside of our house. We logged off and logged back on only to find that the world hole consumed the entire world but the chunk we logged off on. We then decided to create another world to see if the problem was there to. Unfortunately, the world holes were there to. We then uninstalled then re-installed the modpack, but to no avail. I then deleted the modpack from the technic site, and the site I was hosting it from, I remade the modpack (using the same folder/file) and the world holes were still there. I then went onto the other modpacks that I've made and there were no signs of world holes anywhere. So I was just wondering if there is any way I could get rid of these world holes so my friends and I wouldn't have another "incident" like the last one. Advanced OpenGL is off (as suggested by someone else)  and f3 +a doesn't work. Thanks for any input you can offer

[Torezu]

Power failures corrupt world files.  The best option is to load from pre-failure backups.  The second best option is to reset the missing chunks with MCEdit and take the loss.  The third (imo) best option is to pull chunks out of a backup with MCEdit and paste them in where the missing ones are in the world.  The fourth option is to make a new world.

You should not have actual missing-content world holes in a brand-new map, even with the same modpack, as long as you don't use the exact same world name/seed.