Boot Camp: Partition alert message when using Boot Camp Assistant

When upgrading Boot Camp to Windows 8.1 or later, you might see an alert message, "The startup disk cannot be partitioned or restored to a single partition."

This symptom may occur if you have partitions on your startup drive in addition to the following:

  • one OS X partition
  • one Boot Camp partition
  • one OS X Recovery partition (normally not visible in Disk Utility)

If Boot Camp Assistant detects a Microsoft Reserved (MSR) or Windows Recovery partition on your hard drive, you may see this message. These additional partitions are created when performing an upgrade install from Windows 8 to Windows 8.1. The Boot Camp Assistant cannot continue until the extra partition is removed.

Microsoft Reserved and Windows Recovery partitions can be identified as unmounted partitions with the name "disk0s3" or "disk0s5" in Disk Utility. To remove these partitions, use OS X Disk Utility.

Important: Deleting the wrong partition can cause data loss. Be sure to back up both your OS X files and Windows files before attempting this procedure.

  1. Open Disk Utility from the Utilities folder.
  2. Click the Partition tab.
  3. Look for an extra partition named “disk0s3" or “disk0s5”. Select this partition so it is highlighted.
  4. Click the Remove Partition button ( - ).
  5. Make sure the partition you selected is noted in the sheet that appears.

  6. Click Remove.

When Disk Utility finishes, close the Disk Utility window to quit the app. The Boot Camp Assistant can now be used to reinstall or update your existing Windows partition.

Information about products not manufactured by Apple, or independent websites not controlled or tested by Apple, is provided without recommendation or endorsement. Apple assumes no responsibility with regard to the selection, performance, or use of third-party websites or products. Apple makes no representations regarding third-party website accuracy or reliability. Risks are inherent in the use of the Internet. Contact the vendor for additional information. Other company and product names may be trademarks of their respective owners.

Published Date: