GPT Protective Partitions and Windows XP

If you’ve formatted a bootable hard drive on an Intel Mac (or have perhaps been tinkering with the wholly unsupported OSx86 project) and later decided to put the drive to use under Windows XP, you might find that you’re unable to format the disk, with Windows Disk Management claiming the device is a “GPT Protective Partition.” You can’t format it, partition it, or even assign it drive letter. What gives?

The secret is that the GPT scheme protects itself from being read and possibly erased by utilities or operating systems which aren’t able to correctly interpret it. Until just recently, I wasn’t aware that a filesystem even had such a capability. I was under the false assumption that a utility running externally of the drive in question could always format a detected disk, no matter the filesystem in place. I doubt it could withstand the raw formatting power of DBAN, but it was enough to confuse Windows XP.

How can the GPT scheme be undone? Typically, software that can create it can also destroy it. In my case, Leopard’s Disk Utility application was able re-partition the drive as follows:

  • Boot a Leopard DVD (retail or OSx86) and choose your native language at the first screen.
  • Run “Disk Utility” from the “Utilities” menu and highlight the offending drive on the left.
  • Navigate to the “Partition” tab, choose “1 Partition” from the Volume Scheme popup menu, select your new desired format (or “Free Space”), and make sure to click the “Options…” button
  • From the “Options” screen, you can choose between GUID Partition Table, Apple Partition Map (for PowerPC Macs), and Master Boot Record. Choose MBR, and click OK.
  • Click “Apply” to partition the drive using the more common MBR scheme, and thus completely erase all trace of the GPT partition.

Once the partitioning is complete, you’ll be able to format and use the drive under Windows XP, Mac OS 9, or any other system incapable of comprehending GPT Partitions.

GPT Protective Partitions and Windows XP

53 thoughts on “GPT Protective Partitions and Windows XP

  1. Or if you prefer, Linux boot CD to the rescue. Boot up, and at the prompt:

    dd if=/dev/zero of=/dev/[DRIVE_DEVICE_HERE] bs=1k count=2

    That will zero out the first 2KB of the drive. After that, any tool will see it as completely unformatted, and you can do what you like with it.

    Replace [DRIVE_DEVICE_HERE] with the appropriate Linux device node for the drive you want to erase. SATA drives are sda, sdb, sdc, etc. depending on which port they’re plugged into. PATA’s go hda, hdb for primary master/slave; hdc hdd for secondary master/slave.

    Like

  2. Fly says:

    Or use the ‘DiskPart’ tool on the XP command line:

    use ‘list disk’ to find the volume number of the GPT volume, then use ‘select’ to focus on it

    then use the ‘clean’ function and then exit the tool
    ***WARNING*** ALL DATA WILL BE LOST ***WARNING***

    now you can create a new partion and format it.

    Like

  3. Damino says:

    DiskPart in cmd worked a treat for me, thanks Fly! Lots of long frustrated hours have finally come to a winning conclusion! ^_^

    Like

  4. Ron B says:

    A drive I was using with FreeNas was also showing itself as GPT. The comment made by Fly enabled me to format the driver under Windows XP. Great!!

    Like

  5. Matt P says:

    Wow, you guys just saved me from pulling my hair out. I bought a drive off of a friend and have been very frustrated with the whole GPT Protection Partitions thing!

    My friend neglected to mention that the drive used to be inside of one of his Macs…

    Like

  6. Marcello says:

    I just want to say thank you to Fly for the “DISKPART” solution it worked great now I can finally use my usb hard drive.

    THe all thing drove me crazy before.

    Thank you Fly

    Like

  7. Phoenix1e says:

    It worked AWESOME for me thanks,
    Type :
    DISKPART
    get the disk ID with
    LIST
    select the disk to fix with
    SELECT DISK number
    then type
    CLEAN
    I couldn’t partition with windows tool right afterward so I went with (still in diskpart)
    CREATE PARTITION
    PRIMARY
    then just use windows to format :)

    Like

  8. Zebastian says:

    Hey, that DISKPART option worked like a charm!
    Now I can use my drive as a MBR, which is why I’ve been suffering due to protective partitions.

    Like

  9. torque154 says:

    hey thanks a lot it really helped. only reason I noticed this was because I went to plugin my HDD to my windows computer and it wouldn’t mount. I don’t understand the point of this as you can open the GPT drives using linux and could read and write. glad I caught it early enough where I could put it on my other hard drive as it is a 1TB drive.

    Like

  10. jf says:

    freenas formatted gpt-ufs external drive. Had a network worm access drive and delete all mp3, docs and pdfs.

    Only recovery utility able to get it back was UFS File Explorer 3.9.

    And using diskpart command to format it back to ntfs after recovery transfer.

    Like

  11. James says:

    This worked awesome with reformating a disk previously formated with Windows 7 too…

    It worked AWESOME for me thanks,
    Type :
    DISKPART
    get the disk ID with
    LIST
    select the disk to fix with
    SELECT DISK number
    then type
    CLEAN
    I couldn’t partition with windows tool right afterward so I went with (still in diskpart)
    CREATE PARTITION
    PRIMARY
    then just use windows to format :)

    Like

  12. You will not even need to create the partition within Diskpart, just ‘clean’ and exit.
    Then open Windows Disk Management; You will see the cleaned disk as “Offline”. Right click on it´s left-most header on the lower part of Disk management (where size etc. is shown), select “Initialize” – and you are free to partition and format it as required!
    Just did that myself.

    Like

  13. oktapod says:

    thank you.
    I formated my disk with Windows 7. And only it coud open the disk. Now thank’s to the diskpart I can use it in every computer.
    Awesome.

    Like

  14. Dermit says:

    Don’t know who you are fly… but ur def a superfly ;) thanks a mil for the tip! My friend been pi**ed off for a few weeks now about not have his 2 drives working, so last few days i’ve been trying to sort it out and now i checked internet sites and this best way, so simple and quick to complete to. much appreciated!!

    Like

  15. scott says:

    Thought I should add my thanks for the diskpart information. Bought a previously opened harddrive off the shelf at a store. The drive had this GPT protection enabled. This, combined with the create partition primary worked. wonders. Thanks a heap.

    Like

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