Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

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?


share|improve this question

There may or may not be a legitimate reason for this requirement, but I don't think you can get around it. Mac OS X responds very badly to a full startup disk. You absolutely don't want that, and I recommend you always keep a few GB free disk space, just in case temporary files pile up.

Try downloading the update yourself -- maybe it doesn't have this restriction.

Try restarting your system. This clears temporary files and can free up some disk space.

You can usually safely delete cache directories.

Use an external hard drive (you're doing backups for all the data you have, right?) as temporary data storage.

If you're not sure why it is your disk is so full, use a utility such as Disk Inventory X or DaisyDisk to find out. Maybe there are temporary downloads or something similar that can safely be deleted.

share|improve this answer
OmniDiskSweeper is another good choice for looking at disk usage, and it's free. – user135 Jan 12 '11 at 11:07
@Graham I never got its appeal -- what's so much better than Disk Inventory X? Or does it simply depend on visual vs. text personal preference? – Daniel Beck Jan 12 '11 at 11:20
it gets the job done for me with no hassle. I'm pretty sure it's based on some NeXTSTEP sample code called DarkForest, and I liked that app too ;-) – user135 Jan 12 '11 at 11:32

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.