So I ran a erase freespace command: sudo diskutil secureErase freespace 1 /Volumes/Macintosh\ HD in El Capitan and the first time I ran it, I forgot the "Sudo" part and it failed half way. It created the temp file but never deleted it. I ran it a second time with sudo and it worked. I'm still missing about 100GB of space from that first failed attempt, and I can't seem to find where El Capitan stores the temp file. Any ideas where I can find it to delete it?