Windows 7 GPT to MBR? EFI to BIOS

I want to convert my existing GPT partition table to a MBR one. UEFI is giving me too many headaches with Linux.

Actually, I'm just interested in my Windows partition. All the articles on the internet (and questions on superuser?) aim to do the reverse: MBR to GPT.

I've been thinking if something like this would work: Use a Linux LiveCD to 'dd' an image of the Windows C:\ partition (possibly the windows system partition thing too?) to an external device, create a new MBR partition table and install Windows, then copy the dd'ed partitions over?

I bet it's not that simple, and I really don't want to risk all the data on the Windows partition.

Damian

Posted 2013-07-27T02:27:01.340

Reputation: 33

1Do you have a spare hard drive laying around? You could install windows to the new drive, copy the data over, then mirror the drive back over the original windows – spuder – 2013-07-27T03:40:51.863

But why not just continue to use GPT?

– Milind R – 2014-02-15T14:04:54.543

Oh well, at the time I ran into lots of complications I didn't want to deal with when using GPT/UEFI with Linux. I ended up converting the drive to MBR and going back to good old GRUB. I'm surprised this question still sees activity... – Damian – 2014-02-15T22:34:21.490

Answers

gdisk (aka gptfdisk) can convert between MBR and GPT partition tables.

MBR to GPT: Run gdisk on the disk device, press w to "write and exit".
GPT to MBR: Run gdisk, press r for "Recovery", then g for "Convert GPT to MBR and exit".

After converting, you will have to reinstall the right bootloader.

user1686

Posted 2013-07-27T02:27:01.340

Reputation: 283 655

1And that's it? Will it just work™? What about the EFI System Partition, can I simply delete it and merge the free space to the Windows one (right next to it)? – Damian – 2013-07-27T04:28:11.330

3The GPT-to-MBR conversion can be simple or a real headache, depending on details of the partition layout. In particular, more than four partitions means that you'll need to use logical partitions to convert them all, and that in turn imposes partition spacing requirements. Beyond that, the real trick is in getting a Windows BIOS-mode boot loader installed. That will be a big hassle. There may be documentation on the Web, but I don't know where. – Rod Smith – 2013-07-27T14:03:40.990

Use gdisk as @RodSmith and @grawity say.

Then boot into the installer disc, convert the EFI system partition to NTFS. Use bcdboot to put your boot files into the erstwhile ESP. Use bootsect /nt60 /mbr to add a bootsector to your newly converted system partition.

Reboot.

Milind R

Posted 2013-07-27T02:27:01.340

Reputation: 767