I just attempted to install Kali Linux as a dual boot system via a USB. From the Kali OS I partitioned by mac HD and created 20 gigs of unallocated memory. After a mostly unsuccessful install, I bailed and attempted to boot back into OSX. It loaded briefly before showing a black screen with a white circle with a cross through it in the middle.
I attempted to delete the unallocated memory and resize the mac HD to what it was, but I can't get rid of the open space where the unallocated 20 gigs is. Safe boot doesn't produce any different scenario.
Any guidance would be much appreciated.