Was just cleaning my MBP (Retina) with CleanMyMac, and for the fun of it made a "Command + I" on the Harddisk icon -well its a SDD so please bear with me being and old-timer calling it a Hard-disk. My HDD/SDD is a 500GB drive but after cleaning I got serious amount of space, indeed spring cleaning!!! Command + I says I have a capacity of 498.93 GB and available is the 3.66 PB!!! Yep 3.8 Penta Byte. Just for the record then 1 Penta Byte is 1,000 Tera Byte Who says OS X is not geared for the future!!