So I tried using Boot Camp Utility to install Windows 10. It partitioned fine but during Windows 10 install it failed. Boot camp utility says it can't do anything because it doesn't recognize the partition now. So I have 50GB of space just sitting there. The new Disk Utility is garbage and won't let me format it as free space so I can merge it with my OS X partition and I can't select it and hit the -, so I'm in a bind. Any help would be appreciated. Thanks!