Q: The selected disk is of the GPT partition style - MBP 2013

hello, i was able to fix this on a intel I5 iMac as follows

- use Disk Utility

- click on the partition tab

- select the partition that was created by bootcamp, in my case it was named untitled but I could tell by the size that is was the one created by bootcamp

- delete this partition by clicking on the minus key

- create a new partition by clicking on the plus key

- give it a name and specify format as exFAT

- restart the computer and hold down the option key until you see the startup options

- select the device that contains your windows install iso image either USB or DVD drive

- win install will ask you to select the partition to install to

- select the partition you created with Disk Utility

- installer will complain that the partition format needs to be NTFS

- click on the Format button and the partition will be formatted as NTFS

- continue with the install

I'd like to add that this so far (still installing) appears to have solved the problem for me on 13" Retina MBP.  HOWEVER!!! it seems to matter that the partition name is "BootCamp".  I first left it as Untitled and that doesn't work at all.

The sfchew instructions worked for me with a new 13" I5 machine.  Thanks!

Now why did I want to put Windows 8 on my beautiful shiny new mac anyway?!?

Mike

Perfect!  Thanks!

--Fred

I love you. You are the bestest person since the history of everything.

FYI everyone:  THERE IS A VERY EASY FIX!  I was attempting this convoluted method of making it work and I made a much simpler discovery!

If you have multiple drives, and the drive you are installing Windows on will not have any other OS files on it, JUST SET IT UP AS MBR!

With disk utility, instead of playing around with the partitions on the drive, just select the drive on the left side and create a single exFat partition.  Disk Utility will make it MBR for you.  It's really very simple.   When you get into the Windows OS install, format the drive NTFS from exFat (Since Apple doesn't support NTFS in DiskUtility.  I don't blame them on this - it would cause them to have to pay licensing fees to Microsoft.  Booooo!)

You only need the goofy hybrid configuration if you are using multiple OS'es on the same drive.

So, for instance, I have my MacPro 1,1 booting Window 10x 64bit and MacOS 7.5.  I had MacOS 10.11 on this but an update wiped out boot.efs (another topic all together really). Since then for some reason I've never been able to boot my MacPro on an unsupported OS.  I think Apple did something to the firmware in the latest OS that prevents MacPro 1,1 from using unsupported MacOS'es.  That's why I pursued Windows, because I'm not ready to pronounce this hardware investment dead.  Whether they did or did not mess with my system, I have grown tired of their ARBITRARY forced hardware upgrade simply because they're too lazy to support 32bit EFI in their later OS'es.  It's been proven that it's not a limiting factor as Piker and others have developed boot.efi files that "thunk" the 64bit commands to the 32bit EFI.  Don't ask me how it works but it does, and frankly it's criminal that Apple has not allowed more modern OS'es on their original MacPro's.  Just goes to show you that it really is all about the almighty $$ with them, despite all their claims to be more interested in the customer than Microsoft and others.  At least Microsoft keeps making sure they build-in compatibility layers for former hardware technologies.

If you read this through, you might detect a bit of hostility towards Apple.  It's because I am not terribly wealthy and have loved Apple tech, even though being a Windows System Admin.  But when they pull crap like this, it really burns me up.  After all, MacPro systems are VERY EXPENSIVE!

So - for all those fellow MacPro users and others who have been abandoned by Microsoft - If you use a full drive for bootcamp, you CAN USE MBR formatted partitions with Windows 7, 8, and 10.  It's a whole lot easier, and there is no disadvantage unless you can't use the full drive for Windows.

Happy Computing!  OOPS(Update.... make sure to keep the name "BOOTCAMP" on the drive when using Disk Utility to make it exFat!)

I have an old MacPro too! But mine is not as old as yours. I have a 3,1 from Early 2008.

After fighting with Boot Camp trying to install Windows on my main drive along with OS X, it finally dawned on me that I have four drive bays and several extra drives. So why not install Windows on its own drive, right? I thought that Boot Camp would just do the right thing if I selected "Erase drive and create a single partition for Windows." I mean, after all, this is a Mac, right? That didn't work. So I tried erasing the drive myself and creating a single NTFS-formatted partition. (I have a utility that can format NTFS, and I probably paid Microsoft a licensing fee. Boo!) That didn't work either. So I tried erasing the drive with Disk Utility's defaults. Once again that didn't work.

It was at this point I got the GPT partition style error. Up to this point I had been getting messages that stated that I had to check the system log files to find out what went wrong. Now that I had a concrete error that I could search for, I quickly found this post. I reformatted the disk as MBR with a single exFat partition named BOOTCAMP. I then rebooted directly into the Windows installer (skipping Boot Camp altogether lest it mess things up again ). And the installation has gone just fine.

Anyway, thanks!

None of the above worked for me.

Use the EFI Boot partition instead of Windows partition when you restart and hold alt. As seen on a youtube video.

Worked for me on iMac