I believe there's a bug in the Finder that will prevent it from calculating folder sizes. I've only run into it a couple times: for example, Size in the Finder's Inspector window always shows -- (which is normal until the Finder calculates the size). In this case, the Finder doesn't calculate the size, but quitting and relaunching the Finder works to restore proper behavior.
Currently Being ModeratedDec 1, 2011 5:33 PM (in response to MarkDouma®)
Anyone run into a bug where the calculated sizes don't add up?
I have a user folder that says it's holding 32 GB of data, (critical on this little MacAir) but if you add up the sub-folders (and my own idea of how full my Mac really is) you can only account for 8GB of user data