If you have a hard drive from a Mac computer (or from a Hackintosh), toss it in a regular PC and decide to install Windows to the drive, you might get the following message:

Windows cannot be installed to this disk. The selected disk is of the GPT partition style.

The reason is because the Mac OS uses the “GUID Partition Table” partition scheme, whereas Windows/DOS use what’s known as MBR (Master Boot Record). For whatever reason, the Windows installer is incapable of changing this (funny because I used to use Windows installation CD’s on drives I absolutely could not format with other operating systems and it always used to work).

In any case, you’ll need another program to repartition the drive first. I recommend Hiren’s Boot CD (once you go to that site, the link is way at the bottom just below the final ad). You can also use something like SeaTools if you’ve got a Seagate hard drive to wipe the thing clean (or another tool from another manufacturer).

The steps using Hiren’s Boot CD:

• Download the ISO on another computer and burn it the image to a CD or DVD.
• DISCONNECT any other USB drives and other hard drives on the computer you’re installing to so that you don’t accidentally delete stuff on hard drives you don’t want deleted! You should only have the 1 hard drive installed!!!!!
• Boot from the CD.
• Choose “Dos programs”
• Choose “Partition Tools”
• Choose “GParted Partition Editor” (it’s GUI and easy to use – if your mouse isn’t detected for some reason you’ll have to go crazy with the tab button though)
• Select the partitions on the hard drive. You might have 2 showing – a 200MB one (probably shows up as fat32) and the other large one that makes up most of the hard drive’s total size (probably shows up as hfs+).
• –To do this, you click “Partition” – “Delete” – after you’ve done it you need to click the “Apply” button to apply the changes. Remember to do this for all the partitions on the hard drive to wipe it clean.
• Now you should only have 1 item showing in the list – the unpartitioned drive. Click “Device” – “Create Partition Table”
• –The default is named fat or fat32 or ms-dos or something. It’s fine. You may have to “Apply” afterwards.
• Now create a new partition. Choose “Partition” – “New” and select “fat32” from the side. You COULD choose NTFS, but I prefer to choose FAT32 so that Windows has to delete it and make a new NTFS that’s guaranteed to work. “Apply” again if necessary.
• Now eject the CD, put in your Windows CD, and hit the reset button on your computer.
• When you get to the hard drive screen on the Windows installer, it’ll have an error message at the bottom (where the old GPT message was) about the drive needing to be formatted as NTFS. Select the “Delete” option. Then click next and it’ll automatically format the drive as NTFS and install.
• Once Windows has finished installing, go ahead and reconnect any 2nd/3rd hard drives you had connected before.

I’ll note that ALL the above steps are probably not necessary. However, I prefer to be thorough, and this is the way I’ve done it both times and it worked perfectly.

It’s odd that the Windows installer is smart enough to detect the GPT partition scheme but not smart enough to overwrite it with an MBR scheme. Fortunately, there are other partition managers capable of doing it, and many are included in the Hiren Boot CD. It’s inconvenient, but it works well.

This issue affects the Windows Vista installation disk. It may also affect Windows 7 install DVD and Windows XP installer CD.