Where you looking? apple icon > about this mac... > storage has been reported by many to be inaccurate.
I believe that get info is correct.
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Be careful when deleting files. A lot of people have trashed their system when deleting things.
Place things in trash. Reboot & run your applications. Empty trash.
Go after large files that you have created & know what they are. Do not delete small files that are in a folder you do not know what the folder is for. Anything that is less than a megabyte is a small file these days.
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Empty the trash. Space isn't reclaimed until you empty the trash in three places!
The trash can...
-- in the dock
-- for iPhoto
-- with Mail
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Run
OmniDiskSweeper
"The simple, fast way to save disk space"
OmniDiskSweeper is now free!
http://www.omnigroup.com/applications/omnidisksweeper/download/
This will give you a list of files and folders sorted by size. Go after things you know that are big.
To see all files, you need to logon to each user on your system and run OmniDiskSweeper