I get a strange error when I tell Bootcamp to create a partition for Windows. I get to the Create a Partition stage. I select 20GB for Windows leaving 91GB (39GB free) for OS X. I then click Partition and it gives me the following error

The disk cannot be partitioned because some files cannot be moved.

Back up the disk and use Disk Utility to format it as a single Mac OS Extended (Journaled) volume. Restore your information to the disk and try using Boot Camp Assistant again.

My disk is formatted in Mac OS Extended (Journaled), I have closed all applications (besides Bootcamp Assistant) and I have even restarted and tried again to see if that might help. Nothing. I can't get it to partition.

I also tried to create the partition using Disk Utility and I got the following error

Partition failed

Partition failed with the error:

Could not modify partition map because filesystem verification failed

Any ideas?

BTW - I am running OS X 10.6.2


I encountered this error a few months ago when I attempted to create a partition. I followed bootcamp's instructions (ie used time machine to backup the entire disk and reformat) and all worked fine.

Took a while to perform the backup and restore though :(

  • Yeah, I was hoping to avoid it though. – mozillalives Mar 12 '10 at 20:47
  • yeah I must admit I put it off for months. Not something I really like doing! – JT.WK Mar 12 '10 at 22:20

Some unmovable system files have been placed in areas on the disk that prevent Boot Camp from repartitioning it as necessary. This is especially common if the disk is rather full, or was rather full then emptied to make space. The advice given by the Boot Camp Assistant is the best way to fix the issue.


I've found a way better solution to this problem. You'll still need around 30 gig of free space for this. I'm not sure if this cures from all instances of that error, but it definitely helped me.

  1. Get Apple's Recovery Disk Assistant
  2. Make a recovery USB drive
  3. Boot from USB drive, select disk utility. For me it did not work if I booted from on-drive recovery option.
  4. Shrink down your Mac Partition to lowest possible. At this point you don't depend on hard drive at all, and partition operation should go just fine. This might take a while.
  5. Boot to your OS X, restore partition back to full size
  6. Open bootcamp assistant and try go for windows again

The entire operation tool like 15-20 minutes.


Alternate, quicker solution to backing up. Remove all unnecessary files and empty your Trash. Try Boot Camp again.

Explanation: The problem is you don't have contiguous space to proceed with the installation. If you have a lot of unnecessary files (e.g. old movies, music, downloads files), you will probably have enough contiguous space after deletion.

Worked well for me.

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