Win 8.1 Upgrade causes GPT/MBR Mismatch

Concerning partitions in general ... am I able to add another partition to the computer after I've setup a bootcamp partition ?

My goal is to shrink the windows partition by 1 or 2 GB, then create a 1-2 GB partition that is FAT32 - I want to have this reside on the drive so that I can store files/data that can be accessed in either OS.

One example of this is Firefox and Thunderbird profiles stored on the FAT32 partition ....

sakman74 wrote:

Concerning partitions in general ... am I able to add another partition to the computer after I've setup a bootcamp partition ?

No

My goal is to shrink the windows partition by 1 or 2 GB, then create a 1-2 GB partition that is FAT32 - I want to have this reside on the drive so that I can store files/data that can be accessed in either OS

Use a USB flash drive.

My Windows 8.1 partition was at the start 800 GB and after i make for windows 100 GB and split the rest in 5 partitions.

It works fine and when i start Mavericks ic can see all the partitions and i can get data from it, like photos or even documents. All the partitions are in NTFS formatted.

In the Windows Disk Managment i can see all partitions from my Mac and Windows.

1)OS x - 2) EFI-3)Recovery-4)Windows and 5) 5 more Windows partitions. = 9 partitions.

Till now, it works fine and no problems at all.

rambus

what exactly is "Boot Camp" ?

just to get more specific .... is it a firmware-based utility that's part of the Apple hardware, or is it just partitioning software ?

I've seen people refer to it in different ways that is confusing somewhat.

If I was in the windows environment, I know I could use disk management to resize my windows partition and add partitions (haven't done it on the mbp, yet). If I do this, would I encounter problems with dual-booting, the MBR and GPT ?

I have a similar problem. Tried to install OS X 10.11 on my Yosemite machine with Windows 10 Preview Bootcamped and now I get the "OS X could not be installed on your machine: A mismatch between the MBR and GPT partition maps is not supported with this operation". Now, I can only access the Windows 10 partition (which is what I'm replying from). I'm trying to install gdisk and I downloaded it from the link in the OP but when I run gdisk64 as administrator I get a "Type device filename, or press <Enter> to exit" command that I don't know what to do with.

If anyone could give me some help, that would be greatly appreciated! Can't figure out what I'm doing wrong.

Thank you in advance!

You are posting on a very old thread. You may want to start a new thread and post the output.

Type

gdisk64 0:

then 'p' and 'q'

Despite this being an old thread, I'd like to preface my reply by saying thank you to Mark (and other contributors) for providing a helpful solution. It's always nice to see people you go the length to respond with detailed/step-by-step information to help others!

That being said, my particular situation involved not being able to upgrade Mavericks to Yosemite in order to install Final Cut Pro X 10.2.1. I'm also running Windows 8.1 via Bootcamp. When attempting to upgrade to Yosemite everything seemed fine until I got the error message "A mismatch between the MBR and GPT partition maps is not supported with this operation. Quit the installer to restart." I quit and restarted the upgrade installer to no avail.

After downloading and running gdisk (link showed in opening post) and following Mark's step by steps instructions, I was able to eliminate the issue.

NOTE: I installed and ran gdisk from within Mac OS terminal, not Windows. I initially tried in Windows (via command prompt), but wasn't able to get things to work for some reason.

After rewriting the BOOTCAMP partition via gdisk (as noted above - not a physical deletion), and closing out the operation following successful completion/verification, I IMMEDIATELY restarted in Bootcamp to insure everything was still intact. Thereafter, I returned to Mac OS and successfully completed the upgrade to Yosemite without any issues. Next, I went back to verify that Bootcamp was good following the upgrade as I read several older threads of the Yosemite upgrade affecting Bootcamp partitions. Once I verified Bootcamp was good, I logged back into Mac OS to install Final Cut Pro X 10.2.1

In closing, I'm very glad I ran across this post containing helpful instructions as it prevented me from entirely removing the Bootcamp partition (via Bootcamp assistant) and starting over. That would have involved reinstalling Windows and all my applications (or at the very least, imagining and reinstalling an image backup of Windows C:\).

I hope someone else is fortunate to find this helpful despite it being an older post.

Cheers!

@ Aquethys - I had the same issue/question, but later ran gdisk from within Mac terminal instead of Windows.