I want to do the update to the latest version of Mac OS X Sierra. When I launch the update I get following error message:

This Disk doesn't use the GUID partition Scheme

Use Disk Utility to change the partition Scheme.

Select the disk, choose the Partition tab, select the Volume Scheme and then click Options.

It is a 2012 MacBook Pro. The original HDD was replaced with a new SSD drive a few month ago. To do the replacement, I used Super Duper to clone the 2 drives.

When I do diskutil cs list, I get

No CoreStorage logical volume groups found

When I do sudo gpt -r show /dev/disk0, I get

start size index contents

0 1 MBR

1 1

2 976773166 1 MBR part 175

What should I do?

5 Answers

In Disk Utility, near the close/minimize/fullscreen buttons, you can see a "View" mode dropdown menu. Set the view mode to "Show All Devices", then you'll see the "root" drives. Click on a root drive, and then click on the "Erase" button. Now an option to change the "Scheme" from Master Boot Record to GUID appears in the Erase subwindow.

1

In Disk Utility, near the close/minimize/fullscreen buttons, you can see a "View" mode dropdown menu.

Set the view mode to "Show All Devices", then you'll see the "root" drives.

Click on a root drive, and then click on the "Erase" button. Now an option to change the "Scheme" from Master Boot Record to GUID appears in the Erase subwindow.

**If you still don't see the GUID option, unmount the disk and then erase the root drive

Now an option to change the "Scheme" from Master Boot Record to GUID appears in the Erase subwindow. **

Hope this helps

I think you have three alternatives.

1. Do exactly what the error says, run Disk Utility & format the drive as GUID/HFS+ instead of its current MBR/HFS+
   This is destructive & will erase all data
   [Something may have changed in Sierra, which I don't yet have - Volume Scheme is not an option in El Capitan from that tab, only from the Erase tab; so it might be worth checking out to see if it can be done on the fly now]

2. Re-clone back to the original drive as a backup, then do 1. & clone back.
   This is non-destructive but will take some time.

3. Use a Utility like Paragon Hard Disk Manager which is capable of converting MBR to GUID on the fly, non-destructively. It has a 30-day trial. I'd still recommend a backup - things can always go wrong.

BTW, CoreStorage is optional unless you intend to use FileVault or set up a Fusion drive.

For anyone else having a similar issue, this may help. I had installed a brand new 2.5" SSD into a late 2011 MacBook Pro. The Disk Utility on my macOS 10.13 installer USB would not create the proper GUID partition--the GUID option was simply not there, and macOS 10.13 would not install on a non-GUID disk. I then shut down, and used the Disk Utility on a macOS 10.12.4 USB installer, to properly partition the SSD with GUID. Then I shut down, and installed 10.13 using my 10.13 installer USB. All good here.

Finally I could solve this, but it's a bit tricky. Use MS tool called WinPE to convert to GPT forcedly. This solution would work till 2016 model since USB-C model doesn't recognize keyboard on WinPE.

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