Windows – Cannot install Windows 8 because it can’t create a new partition

I know its old news but if anyone else needs a hand regarding removing the Hybrid MBR, you could try gdisk utility.

I was attempting to install Windows 8.1 on my MBP 2011 8,3 using the EFI method last night and the EFI installer would complain at the partitioning step that Windows couldnt be installed onto the partition I wanted as it could see the MBR partitions of the Hybrid MBR/GPT. Windows 8 doesnt try to look for a GPT partition once it finds an MBR one and so as you suggest, it can be removed which will hopefully make the Bitlocker tool happy as well.

This Stack Overflow question advises how to remove the Hybrid MBR. I'll quote the relevant bits from that answer here which is what I did last night to get around Windows 8.1 installer complaining about the hybrid MBR/GPT. Full kudos to Rod Smith for his excellent tool, website and and post.

The solution in this case is to clear the hybrid MBR data. A number of utilities can do this. I'll describe how to do it with my own GPT fdisk (gdisk) utility:

1. Download GPT fdisk from its Sourceforge page and install it. (Versions are available for Linux, OS X, and Windows. I'll assume you'll do this from OS X.)
2. Launch gdisk on your disk by typing sudo gdisk /dev/disk1 in a Terminal window. (Change the device identifier if it's not as you presented earlier or if you use another OS for the job.)
3. Type p to view the partition table to verify you're working on the correct disk. If not, type q to quit without saving your changes and try again with another device.
4. Type x to enter the experts' menu.
5. Type n to create a fresh protective MBR. Note that gdisk won't confirm a change; it'll just show you a new experts' prompt.
6. Type w to save your changes. You'll be asked to confirm this action. Do so.

Some other resources on the gdisk page

• Repairing GPT Disks: http://www.rodsbooks.com/gdisk/hybrid.html

On a normal hard disk installation of most any EFI-based OS, you'll have, at a minimum, one FAT EFI System Partition (ESP) and one partition for the OS itself. The ESP holds a boot loader for the OS, possibly along with files to support the boot loader (fonts, configuration files, drivers, etc.), and possibly even the OS's kernel. The OS partition holds more-or-less the same OS files you'd find on a BIOS-based installation of the same OS. Depending on the OS, you might have additional partitions, too -- data partitions, a swap partition, etc.

There can be exceptions to this rule, particularly for installation media or emergency disks. For instance, you could put the whole OS in the ESP. Also, most EFIs are happy to boot from partitions that are not ESPs, so you could just have one big non-ESP FAT partition, as you've got. This can work fine for an emergency disk, but I wouldn't recommend setting up a regular OS installation in this way; I'd use a separate ESP and OS partition.

Note that a standard EFI can read FAT, but cannot read NTFS, ext2/3/4fs, HFS+, or any other filesystem. (Apple's EFI can read HFS+, and so can read its boot loader from a Mac OS X root partition rather than from the ESP, but Apple's EFI is the exception rather than the rule. A few EFIs also have ISO-9660 filesystem drivers -- but again, they're exceptions to the rule.) Because FAT is the only filesystem that's guaranteed to be readable by EFI, an attempt to build a boot disk that does not include a FAT partition is doomed to failure, except of course when used on those unusual EFIs that support additional filesystems.

I can't provide a procedure to set up a Windows emergency disk to use separate EFI and Windows partitions, since I'm more of a Linux person than a Windows person. Unless you run into a specific problem with your approach, though, I'd just stick with it; at least you know it works.