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How to change partition from MBR to GUID?

I am trying to update to High Sierra but it won't let me because my disk is partitioned using MBR. I am kinda confused because even though i have recently installed a new hard disk, I have OS sierra running on the disk currently and my understanding is that OS sierra cannot run in MBR any more. Now i am faced with repartitioning my disk to GUID which i understand and acknowledge however when i go to disk utility i am not even able to select the partition panel for this disk. How do i repartition my main disk to GUID and reinstall the most recent version of OS sierra?? All the old articles give processes that are no longer relevant (i.e. use and install disk). Anyone help?

MacBook Pro (13-inch Early 2011), macOS Sierra (10.12.6)

Posted on Nov 12, 2017 3:05 PM

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Posted on Nov 12, 2017 3:09 PM

Install El Capitan or Later from Scratch


Backup if possible before continuing.


  1. Restart the computer. Immediately after the chime hold down the CommandandRkeys until the Apple logo appears. When the Utility Menu appears:
  2. Select Disk Utility from the Utility Menu and click on Continue button.
  3. When Disk Utility loads select the volume (indented entry, usually Macintosh HD) from the Device list.
  4. Click on the Erase icon in Disk Utility's main window. A panel will drop down.
  5. Set the Format type to Mac OS Extended (Journaled.)
  6. Click on the Apply button, then wait for the Done button to activate and click on it.
  7. Quit Disk Utility and return to the Utility Menu.
  8. Select Reinstall OS X and click on the Continue button.
1 reply
Question marked as Best reply

Nov 12, 2017 3:09 PM in response to bagabagdeek

Install El Capitan or Later from Scratch


Backup if possible before continuing.


  1. Restart the computer. Immediately after the chime hold down the CommandandRkeys until the Apple logo appears. When the Utility Menu appears:
  2. Select Disk Utility from the Utility Menu and click on Continue button.
  3. When Disk Utility loads select the volume (indented entry, usually Macintosh HD) from the Device list.
  4. Click on the Erase icon in Disk Utility's main window. A panel will drop down.
  5. Set the Format type to Mac OS Extended (Journaled.)
  6. Click on the Apply button, then wait for the Done button to activate and click on it.
  7. Quit Disk Utility and return to the Utility Menu.
  8. Select Reinstall OS X and click on the Continue button.

How to change partition from MBR to GUID?

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