I recently uninstalled a 120 GB windows 7 (installed and uninstalled via boot camp) on my Mac mini machine. I suspect that part of the disk space used in that installation has been made unavailable. Look at the following terminal commands:
$ diskutil list /dev/disk0 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *500.1 GB disk0 1: EFI 209.7 MB disk0s1 2: Apple_HFS Macintosh HD 389.0 GB disk0s2 3: Apple_Boot Recovery HD 650.0 MB disk0s3 $ df -h Filesystem Size Used Avail Capacity iused ifree %iused Mounted on /dev/disk0s2 362Gi 319Gi 43Gi 89% 83772049 11198653 88% / devfs 200Ki 200Ki 0Bi 100% 693 0 100% /dev map -hosts 0Bi 0Bi 0Bi 100% 0 0 100% /net map auto_home 0Bi 0Bi 0Bi 100% 0 0 100% /home
The results above show that I am missing 110 GB of disk space. I know that the operating system itself uses space, but I very much doubt that it is that much.