Is it possible to set up he following combination of partitions; how?

  • two OS X partitions, each bootable (one for the main system, another for testing new OS X releases)
  • a Bootcamp bootable partition for Windows 7
  • data partition shared between OS X and Windows?

I don't need access to either of OS X boot partitions from Windows. And vice versa: don't need to access Windows boot partition from OS X.

I use MacBook Pro 13" 2010, Windows 7 64-bit, OS X Mountain Lion.


It should be possible to partition the HDD like that but not in a default setup with Boot Camp and Windows 8/8.1 is recommended:

The hybrid MBR/GPT necessary for Boot Camp Assistant to install/boot Windows doesn't allow more than 4 partitions:

  • Apple CoreStorage or Macintosh HD
  • Recovery HD
  • your future Windows 8/(7)
  • a place holder in the MBR linking to the GPT (some count the EFI-partition as the fourth one, but this doesn't seem to be true)

So a different approach is necessary:

Skip the hybrid MBR and use a pure GPT setup. Alternatively a multistage boot loader setup with rEFInd may also be possible.

Here is an obviously working setup for Windows 8 (source):

Check the comments there before proceeding.

Windows 7 may work as well with this guide. Here is an opposing point of view which claims that it is impossible to install Windows 7 in native UEFI-mode.

Warning: These steps require you to completely erase your hard drive! Make sure you have all the materials and have backed up all of your data before proceeding.


  • A recent MacBook Pro (this will probably work on other Macs, but I don’t have any to test with) I’ve tested this on the 1st-gen Retina 15″ and a 13″ 2nd-gen i5 model.
  • A disk drive capable of reading DVDs (you’ll need an external drive for MacBook Retinas or MacBook Airs)
  • A Mountain Lion Installer thumb drive
  • A CD/USB drive with the “Windows Support” files from Bootcamp
  • A Windows 8 Pro Install DVD


  1. Put the Windows 8 Disk in the disk drive
  2. Option-boot the computer and choose to boot off the “Windows” disk (Do not choose “EFI Boot” but make sure that it does show up, you’ll need to use it later)
  3. Once the installer gets to the setup screen, hit shift+f10. This will bring up a command prompt
  4. Type the following commands (this assumes that you only have one hard drive):
    1. diskpart (this puts you into the windows partitioning shell)
      1. select disk 0 (this selects the primary hard drive, make sure you don’t have any extra drives connected)
      2. clean (this erases your entire hard drive by removing all partition information)
      3. convert gpt (this converts your hard drive from an MBR partition table to a GUID partition table)
      4. create partition efi size=200 (this creates the efi partition where the bootloader will live)
      5. format fs=fat32 (this formats the EFI partition as fat32 so that Windows can write to it)
      6. create partition msr size=128 (this creates a “MicroSoft Reserved” partition… because microsoft)
      7. create partition primary (this uses the rest of your free space to create a usable partition)
      8. format fs=ntfs quick label=Windows (this formats the Windows partition and labels it as “Windows” which is what OS X will see)
      9. exit (this exits the windows partitioning shell)
    2. wpeutil reboot (this tells the computer to reboot)
  5. Option-boot the computer when it reboots, but this time choose “EFI Boot” instead of “Windows” Remember to press the any key to boot into the installer!
  6. Choose to use a Custom Install and install Windows 8 to “Partition 3″ (The only primary partition) Make sure you leave the install disk in the drive through the whole install or you could get a BSOD
  7. Install the Windows Support software from your CD/USB drive to gain full functionality of your computer Congratulations! You now have a natively-EFI-booting Windows 8 Install! Now, on to dual-booting OSX…
  8. Open “Disk Management” in Windows. Find your “C Drive” partition and resize it by right-clicking on it and choosing “shrink volume”
    1. Shrink it by the size you’d like your OS X installations and the shared volume to be (e.g. if you want to give the 3 partitions 200GB, use 204800MB)
    2. Right-click on the now empty area at the end of the drive and make 3 new “Simple volumes” Don’t format it.
  9. Reboot the computer into your OS X Installer thumb drive
  10. Open Disk Utility
    1. Choose “disk0s4″ as this will be the 4th partition on disk 0
    2. On the “Erase” tab choose “Mac OS Extended (Journaled)” since this is what OS X likes to use.
    3. Give it a label that you like (e.g. “SystemML”)
    4. Hit Erase
    5. Choose “disk0s5″ as this will be the 5th partition on disk 0
    6. On the “Erase” tab choose “Mac OS Extended (Journaled)” since this is what OS X likes to use.
    7. Give it a label that you like (e.g. “SystemExperimental”)
    8. Hit Erase
    9. Choose “disk0s6″ as this will be the 6th partition on disk 0
    10. On the “Erase” tab choose “ExFAt”.
    11. Give it a label that you like (e.g. “WinMacShare”)
    12. Hit Erase
    13. Exit Disk Utility
  11. Install OS X on your new partitions.

If step 8.2. fails you have to partition the unallocated space manually after step 9 in Terminal.app with

gpt -r show /dev/diskNumber

to get the partition table, and

gpt add -b StartBlock -i IndexNumber -s SizeOfPartition -t PartitionType diskNumber

to add partitions.

You have to format the volumes afterwards with Disk Utility.

| improve this answer | |
  • Thanks. So talking about Windows 7 x64 (which the original question is all about), what about "Windows 7 x64 (64-bit) only supports installation on a UEFI 2.0 firmware using a GPT partitioned disk" vs "Apple Macintoshes implement the EFI 1.1 standard" problem? – yurkennis Mar 10 '15 at 10:23
  • @yurkennis At the Moment i don't have the means to test it with a real Mac. If I were you I would just give it a try with a regular Windows 7 x64 DVD. There is a chance that it will work since both Davids use different approaches to get things done. – klanomath Mar 10 '15 at 10:45

Windows 7 and previous has a limitation of being on a drive with no more than 4 partitions. When BootCamp partitions a Mac HD and adds the Windows (NTFS) partition that makes the fourth partition, so if you add more after that Windows will likely become unbootable.

Your plan has a total of 6 partitions, two of them hidden (and rather small) a boot partition and the system repair (bootable) partition. So it looks like you only have four. If you go into Disk utility you can see the other ones (may have to turn on debug mode to see them tho, don't remember...)

You may have to add a HD to the system to do what you want.

Note this info may have changed with Windows 8, I'm not sure.

| improve this answer | |

I used to believe that I solved the problem, but my solution only lasted a few months. For the record, here it is, in a nutshell:

  • create as many OS X partitions as required; Bootcamp partition and shared FAT32 data partition--all under OS X
  • now use gdisk from gptfdisk (as detailed in this post) to create MBR containing only Bootcamp, Shared and one of the OS X partitions chosen (so effectively MBR becomes a subset of GPT limited to only 3 partitions)

This setup lasted a few months until the shared partition became corrupted. Looks like it happened after a minor software update under one of OS X instances, which, in my belief, didn't involve recover partition--but I may be wrong.

Now I'm looking for a best way to recover that shared partition--see a separate question on that.

| improve this answer | |

The answer is YES. My mid 2007 iMac is currently configured in such a fashion. My Windows 8.1 uses a BIOS boot. I have two NTFS partitions, one exFAT partition and two HFS+ partitions. (I also have the hidden EFI partition and the hidden OS X recovery partition) The exFAT partition is read/writeable from all operating systems.

Do you need to keep your current Windows and/or OS X operating system partitions? Or, will you be starting from scratch and erasing everything? If you need to preserve your existing windows system then I would recommend using WinClone (cost $30) to move the operating system (preferably) off computer to external storage temporarily. OS X can be backed up and move off computer using the disk utility.

To complete the install, you will probably need to boot from a flash drive containing a copy of the hidden recovery partition. Do you still have your hidden internal recovery partition and does it work? (Better yet if you have already made a flash drive copy) If you don't know the answer, then reboot your computer, then hold down the alt/option key and see if the recovery partition appears.

I assume you have installed windows 7 on the mac before. If not, then do you know if you get "Select CD-ROM Boot Type:” error during Windows install described here? If you do, then you will need to make a new install DVD.

To get things to work, the idea is to do everything opposite of what apple tell you to do. I would recommend the following steps (assuming the internal disk can be erased and you are saving nothing.)

  1. Boot from the flash drive.
  2. Create a new GPT partitioned disk using the Disk Utility. The first partition will be for Windows 7, so format it "MS-DOS (FAT)". The second partition will be ExFAT formatted. The third and fourth partitions will be for OS X so choose "Mac OS Extended (Journaled)".
  3. Exit the Disk Utility and select install OS X from the internet.
  4. Boot to the installed OS X. Open a Terminal window and enter the command:

    sudo bless --device /dev/disk0s2 --setBoot --legacy

  5. Insert the Windows 7 DVD and reboot the computer. Hold down the alt/option key and select the DVD to boot from. Hit the space bar when prompted to continue booting from the DVD. (You only do this once.)

  6. Install Windows 7. Make sure you install to the correct partition and format the partition NTFS.
  7. Install bootcamp drivers stored on a MBR partitioned, FAT formatted flash drive. The drivers can be downloaded under OS X from here. I suppose the drivers could also be copied to and installed from the exFAT partition.
  8. Enjoy hours of installing hundreds and hundreds of updates.

Of course, I have left out many details, but most of the time no one responds. After I while, I learn not to spend to much time on an answer, unless someone shows interest.


I no longer use ExFat formatted internal partitions. I found ExFat to be unreliable. I now use MS-DOS(Fat).

| improve this answer | |
  • Are you sure the entire process will work for Windows 7, on a MacBook Air mid-2011? – yurkennis Apr 1 '15 at 21:22
  • No, I am not sure. I do not own a MacBook Air mid-2011. If I did, there still could be a chance the hardware would be difference from your model. My current inventory of Macs is the iMac 2006, 2007 and 2011 models. Have you changed computers? Your original question referred to a MacBook Pro 13" 2010. If you answer my questions, I can edit my answer and add more details on how to proceed. – David Anderson Apr 1 '15 at 23:28
  • @yurkennis: Do you actually have a question? I noticed of the 26 questions you have asked, you answered 16 of them. Of the 16, you gave yourself credit for the correct answer on 14 of the questions. You have only given someone else credit of a correct answer once. I guess this is permitted. I know I have asked/answered/credited my own questions. – David Anderson 4 hours ago – David Anderson Apr 2 '15 at 3:11
  • Ooops, I meant 13" MBP late-2010 of course. – yurkennis Sep 6 '15 at 18:34
  • I will likely try to follow this howto, so there are few questions to ask: – yurkennis Sep 20 '15 at 18:18

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