Q: How can i remove a hybrid mbr from my system drive so that Efi booted windows will install.
Hi,
i have just clean installed OSX lion on a freshly wiped drive in my macbook pro, using a bootable lion installer usb i used disk utility to partition my drive into a mac and a windows partition under the GPT/GUID partition scheme, i then proceeded to install lion onto the mac partition, and completed the set up, All Good...
so i plug in my Windows 8 EFI Boot USB stick (Notice, EFI boot here, NOT BIOS EMULATION BOOT), shutdown and power on the mac and proceed to the boot picker by holding option, So far so good, the usb key is recognised and the system boots into the Windows Setup in EFI mode, Enter product key, accept terms and so on, Now i select my Windows partition and windows Says That it cant install to Partition 4 (EFI Partiton, OSX Lion, Lion recovery, Windows), It says that it can only install to a GPT / GUID based disk as expected...
Why is there a protective MBR on my drive when i didnt add one, and i have not even touched bootcamp assistant...
How can i remove this Protective MBR from my drive so that my disk is PURE GPT so windows can install?
hours of googling has turned up nothing...
System:
Macbook Pro 13 inch Mid 2009
Mac os: OSX Lion
Version of windows trying to install: Windows 8 Release Preview 64 bit in EFI Mode
MacBook Pro (13-inch Mid 2009), Mac OS X (10.7)
Posted on Jun 21, 2012 7:22 AM
Alexander, I would like to apologize for the TERRIBLE answers you have been given so far. I too had this question, and so here is what my thoughts are, as maybe they might provide insight in leading you towards the answer.
I am a *nix user in general, and thus own a mac and a thinkpad. In fact I just got my thinkpad not too long ago. As such, I transfered my faster hard drive to my faster computer, which made logcal sense to me. Ergo, I moved my Mac drive to my lenovo. On this drive I have a hybrid mbr which is no longer needed. So my thoughts are this:
From what I gather, the UEFI standard indicates that there is to be a protective MBR on all GPT systems. This is so that when you use programs that are not GPT aware, they will see a presumably "full" drive and not think that they have the right to destroy your existing data in what it thinks is free space. For instance, fdisk or other MBR only partitioning systems. Thus, if your system has only a MBR with a single EE partition, it would be my guess that it was in fact not put there by installing Windows, but rather for the protection of your system.
If you are in my situation, where you do indeed have a hybrid MBR with written out partitions, it would be my guess that the only way to rid yourself of it is to do it manually. The way I would recommend, is using gdisk (gpt fdisk). It is command line only, but the syntax is pretty easy:
$ sudo gdisk /dev/disk0
Assuming you are using your mac partition and your primary hdd is disk0. That will put you into an interactive session of gdisk. Enter "?" for command options. What you need is the "recovery and transformation" section which is the "r" I think. From there I would say you probably want to create a new hybrid mbr (you will be using this to delete it). When it asks you for the partitions you would like to include, just hit enter. It should then ask you if you would like to create a protective entry for the remainder of the empty space. This is what you want so tell it to do that. After you are done, "w" will write and exit. You may want to first use the "p" to print and ensure that you have what you want. You can proabably check your work by using fdisk as so:
$ sudo fdisk -l /dev/disk0
I hope this helps you, and if you find that there is a better way, I hope you might enlighten this thread.
Cheers!
PS The command examples, the $ is to indicate it is a bash/shell command as a non-root user, do not include it in the command.
Posted on Jul 18, 2012 2:54 PM