Mac OS X 10.4, 10.5, and 10.6: FileVault - "There isn't enough space on your hard disk..." alert


When turning FileVault on or off in Security preferences in Mac OS X 10.4, 10.5, or 10.6, this alert may appear:

"There isn't enough space on your hard disk to turn on (or off) FileVault"

The amount of free space stated as needed may be much greater than what is available ("4000 GB of free space is needed" may appear, for example).


Create a new user account and transfer your data to the account via a sparse disk image. Afterwards, enable FileVault on the new account (or leave it off) if desired, then delete your original account. Here's how to do all that:

Important: Before performing these steps, you should back up your data (or your entire home folder) as a precaution.

  1. Start up in Safe Mode.
  2. Log in to your account if you haven't already.

    Create an interim disk image to transfer home folder files to

  3. Open Disk Utility (in the Utilities folder, in the Applications folder).

    : Do not open any other applications while completing these steps.
  4. From the File menu, choose New > Blank Disk Image... .
  5. From the Format: pop-up menu of the Blank Disk Image window, choose "sparse".
  6. Adjust the Size pop-up menu. The disk image should have enough capacity to hold the contents of your home folder (directory). You can choose "Custom..." from the Size pop-up menu to enter a specific size if needed (if you need more than 4.7 GB, for example).

    It's OK if you make the image a little larger than you expect you'll need.
    For example, if you have 2.3 GB of stuff in your Home, you might create a 2.6 GB (or larger) image.

      How large is your home folder?

      If you aren't sure how big your home folder (directory) is, follow these steps:

      1. From the Finder's Go menu, choose Home.
      2. Select all items in the window (or press Command-A).
      3. If your home folder has eleven or more items, from the File menu, choose Get Info (or press Command-I).

        If your home folder has ten or fewer items, hold the Option key, then from the File menu choose Show Inspector (or press Option-Command-I). (If Option is not held, Get Info is the menu choice, and separate information windows will open for each item if there are ten or fewer items selected, instead of a single, cumulative information window.)
      4. Notice the number on the "Size:" line, this is the size of your home folder. You may need to wait a few moments for the size to be calculated depending on how much stuff is in your Home.

  7. Give the image a unique name, but save it somewhere outside of your Home (don't save it on the desktop or in Documents, for example). You could save it at the root level of your Mac OS X volume, or on a different partition or different disk.

    Note: If your hard disk does not have enough free space for the new image, create it on an external disk or different partition which has enough space.
  8. Mount the new sparse disk image.
  9. In the Finder, select the image volume and choose Get Info from the File menu. Make sure "Ignore ownership on this volume" is selected (at the bottom of the window).
  10. Open your home folder (from the Go menu, choose Home).
  11. Select all items in your Home and drag them (copy) to the mounted sparse disk image. Advanced note: Invisible files or folders might not be copied; usually this should present no issue or only a minor issue--for example, ssh users will need to accept the ssh key after completing these steps.

    Create a new user account

  12. From the Apple menu, choose System Preferences.
  13. From the View menu, choose Accounts.
  14. Create a new account that has the same privileges as your original, current account (enable "Allow user to administer this computer" if it is enabled for your current account). You may wish to give it a name similar to your current account.
  15. Log out of your account and log in to the new account created in the previous step.

    Copy files from the disk image to your new account

  16. Mount the same, new sparse disk image that you copied files to.
  17. In the Finder, select the image volume's icon and choose Get Info from the File menu.
  18. Make sure "Ignore ownership on this volume" is selected (at the bottom of the window).
  19. Highlight all items in the sparse disk image and drag them into your new account's home folder (from the Finder's Go menu, choose Home). You may be prompted to confirm that you wish to replace some items.

    Again, you should not open any other applications during this process.
  20. Restart when the copy has completed.
  21. Log into the new user account and verify that all desired data has been transferred and that you can open files as expected (things on your desktop or in your Documents folder, for example).
  22. If desired, enable FileVault for this account in Security preferences.

Reclaiming disk space

If you wish to reclaim disk space, use Account preferences to delete the original user account. You can also delete the interim sparse image. Important: Do not delete these unless you are sure that all files have been properly copied (advanced users should make sure any needed invisible files were copied, if not you can use Terminal to copy or move them).

This document will be updated as more information becomes available.

Last Modified: May 24, 2012
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  • Last Modified: May 24, 2012
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