Software Update has notified me of a new OSX system update (including the Mac App Store). It claims to be about 1.6GB in size. I have 4.6GB of free space on my hard drive. However, when I attempt to actually run the update, it fails because it claims to need 6.9GB of free space. Is there any particular reason Software Update needs so much space beyond the downloaded file size and are there any work arounds?