A friend of mine has a fairly new MacBook Air with 256 GB SSD. According to the hard drive info (Command+I) it has a capacity of about 250 GB and only 5 GB available (with emptied trash). However, when I open the hard drive and add up the GB of all folders I get a total of just 190 GB - which means that about 60 GB should be available. The difference seems to be in the home folder that shows a total of 215 GB while the folders in it only sum up to 160 GB. Putting something into the trash and emptying it again or restarting the computer make no difference. What could be going on here and how can it be fixed? Thanks.