Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

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

I was trying to create a new partition on my macbook by booting through Recovery USB using the disk Utility. But I am unable to create a partition since it throws a "Cannot unmount disk" error. I tried to manually unmount the drive but it doesn't work.

share|improve this question
    
You can't unmount it because the Recovery Partition HD is on that drive. – user3463 Sep 20 '11 at 5:40
up vote 0 down vote accepted

Try Erasing the the existing partition first. If the drive has been claimed by CoreStorage, you won't be allowed to change the partitions until it's clean.

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .