I want to delete my Windows partition and regrow my Mac partition to use the whole disk. But when I click Restore in the Boot Camp Assistant, it says:

Your disk could not be restored to a single partition.

An error occurred while restoring the disk to a single partition.

I'm using Mac OS X 10.8.5, on a mid-2009 MacBook Pro.

  • 1
    Lol, StackOverflow gave me a Popular Question badge for this. Zero upvotes. – mcandre Jul 22 '14 at 13:50

WARNING: This answer may cause a problem with El Capitan! Read Warren Pena's comment below. If anyone knows how to get the disk space back on El Capitan after doing this then please comment below.

I had this issue and I solved it by doing the following.

  1. Go to "Disk Utility.app"
  2. Select your Windows Partition
  3. Click "Erase" and select "Mac OS Extended (Journaled)"
  4. Erase the partition
  5. Once that has completed, select the Complete Disk (Not Partitioned) enter image description here
  6. Now select "Partition"
  7. Select the newly Formatted "Windows" partition and select the "-" symbol at the bottom to remove the partion
    enter image description here

  8. You should see an empty space where the partition was

  9. Select your main partition, and to the right where it says "Size", type the Disk's full size and hit enter
    enter image description here

  10. After Disk Utility completes the resizing, you should now have a single, full partition again.

  • This might have been effective at the time, but it ended with a rude surprise for me on El Cap: The Boot Camp partition is gone, but the space it was using is also also gone. It's not available for me to reallocate to the main OS X partition! – Warren Pena Jun 13 '16 at 5:05
  • 1
    Worked for me on Sierra – geometrikal May 20 '17 at 20:09
  1. Go to Disk Utilities
  2. click the Windows Partition and then Format It as Mac OS X Journaled
  3. then click Enable Journaling on the Disk Utility Toolbar
  4. then go to the MAIN DISC and Click on the Partition tab
  5. remove the Windows Partition which is now "Mac OS X Journaled"
  6. after removing it, resize the partition size of the main partition to the maximum

Then, you should have your full sized disc for use and you can use bootcamp later.

  • In newer versions of Disk Utility, "Enable Journaling" is available under the File menu. – tutuDajuju Nov 8 '15 at 9:04
  1. Go to Disk Utilities
  2. Select Windows partition and make sure you MOUNT IT
  3. Once Windows partition is mounted, return to Boot Camp Assistant
  4. Re-try Restore and it should run OK now and restore the Mac partition to the size of the whole disk.

Today I tried the various suggestions above, but couldn't restore the Mac partition. This may have been in part due to the fact the amount I initially partition for Bootcamp wasn't sufficient, so decreased the Mac partition and then use Mini-Tool Partition on Windows side to extend my Bootcamp partition.

Instead I used Disk Utility to erase the unwanted partition, and then I was able to restore it through the Boot Camp Assistant.


Just restarting and trying again solved the problem for me.


I fixed it in 10.11.1 El Capitan by formatting the Bootcamp Partition several times to FAT formatting. Then going back into Bootcamp Assistant and telling it to once again restore the original boot partition to size. This then asked to adjust my settings for Bootcamp 4 times. I said yes each time. This removed the Bootcamp partition completely for good.


Disk Utility > view > show all Select the main disk > erase > format using 'partition choice' and good to go.

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