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I wiped my Windows 8 thinking I could install Windows 7 x86 but I can't because the disk is GPT. I need to convert to MBR.

I'm trying to use GParted to convert to MBR but it seems GParted can only do the opposite. Can GParted be made to convert to MBR?

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4 Answers 4

up vote 15 down vote accepted

Since you mentioned GParted, try this:

  1. Launch GParted on the disk.
  2. If any partitions are mounted (as indicated by a lock or key icon), unmount them.
  3. Select Device->Create Partition Table.
  4. Click Apply.

The disk should now use MBR. You can also create partitions within GParted, if you like; however, the Windows installer can do this automatically if you prefer.

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Thanks that works. –  CppLearner Sep 8 '13 at 4:28

If you have a Windows 7 Installation disk, you can enter Repair mode and use diskpart to accomplish this.

From Windows 7 DVD, click Repair your computer when you see this screen:

enter image description here

Then select Command Prompt in the Repair window:

enter image description here


Once you've entered the command prompt, type diskpart to enter the utility.

  1. Type select disk # replacing "#" with the drive number of the one you wish to format. To see a list of disks, type list disk.
  2. Type clean. This deletes all volumes from the drive.
  3. Type convert mbr to convert the disk to mbr.

Note: You can repeat this process and in step 3 replace with the command convert gpt to go back to GPT.


Sources: Change a GUID Partition Table Disk into a Master Boot Record Disk, Change a Master Boot Record Disk into a GUID Partition Table Disk

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Thanks. Exciting news, but it said I need to use Windows 8 disc to repair; as soon as I click repair it said incompatible OS. –  CppLearner Sep 8 '13 at 2:04
    
If that doesn't work you could use a partitioning tool like EaseUS Partiton Manager. It has a bootable version that supports conversion to and from GPT (it also has support for doing so without data loss). –  Moses Sep 8 '13 at 2:10
    
I didn't try this method but it works. I believe your method will work so I will also upvote. –  CppLearner Sep 8 '13 at 4:28
    
From @JasonErickson: You can clean the disk with diskpart by booting any windows Vista,7,8.x,2008.x,2012.x install media. When the welcome screen comes up press "Shift+F10" and it will bring up a command prompt window. Then type diskpart. Then follow the previous directions to clean the disk and convert to MBR. This is an alternate route to diskpart. –  fixer1234 Jan 24 at 18:44

For those of who who find this on a desperate google trawl like myself.

Inside the windows 7 installer, you can launch command prompt with CMD F10, then follow the previous post's advise with regards to diskpart...

Once you've entered the command prompt, type diskpart to enter the utility.

Type select disk # replacing "#" with the drive number of the one you wish to format. To see a list of disks, type list disk. Type clean. This deletes all volumes from the drive. Type convert mbr to convert the disk to mbr. Note: You can repeat this process and in step 3 replace with the command convert gpt to go back to GPT.

share|improve this answer

You can clean the disk with diskpart by booting any windows Vista,7,8.x,2008.x,2012.x install media. When the welcome screen comes up press "Shift+F10" and it will bring up a command prompt window. Then type diskpart. Then follow the previous directions to clean the disk and convert to MBR.

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This is a repeat of the @Moses answer. It just gives an alternate route to access diskpart. That minor variation should just be noted as a comment on the other answer, which you need a little more rep for. I've moved the information there so it isn't lost if your answer gets deleted. This answer would be considered low quality because it doesn't add something significant to what has already been posted, so people could downvote it. You might want to delete it so any downvotes don't eat into your rep. –  fixer1234 Jan 24 at 18:47

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