Accidentally formatted brand new HDD to GPT instead of MBR

Alright. So here's my giant-ass screw-up of the year.

I have a computer that is over 5 years old - essentially a stock Dell Studio XPS 8100 (desktop). The hard drive, which I honestly am not surprised about, gave me a warning that it was likely about to fail. Not being an idiot, I went and got a new HDD, plugged it in, formatted it (this is where I screwed up, as far as I can tell) into GPT, and made a full system image on the new HDD and a recovery DVD. Unplugged the old HDD, attempted to boot up and restore the image to the new HDD.


Apparently my motherboard doesn't support GPT, at least not for booting.

Now, of course my first step would normally be to plug back in the old HDD, reformat the new one into MBR, and rinse and repeat...but the old HDD chose that moment to fail (near as I can tell. BIOS seems to still recognize that it exists, but attempting to boot the computer up gives me the AHCI Port0 Error)

My question to you all is threefold:
1. Can I reformat into MBR without the system booted into Windows?
2. Can I do this without data loss? I have some things that I would very much like to keep.
3. If either of the above is a no, can I get a new motherboard that does support GPT and replace my old motherboard, and make my problems disappear?

And of course, if you all think I'm completely off my rocker with what the problem actually is, feel free to tell me. If you need more information or pictures, I can (probably) get them.

Thanks in advance.

TheGurw said:

My question to you all is threefold:
1. Can I reformat into MBR without the system booted into Windows?
2. Can I do this without data loss? I have some things that I would very much like to keep.
3. If either of the above is a no, can I get a new motherboard that does support GPT and replace my old motherboard, and make my problems disappear?

And of course, if you all think I'm completely off my rocker with what the problem actually is, feel free to tell me. If you need more information or pictures, I can (probably) get them.

Re question 1: I don't think you can convert from GPT to MBR on a disk with partitions. You'd have to use something like a Windows installation disk and go to a command prompt and use the "diskpart" command. I think after you delete the partitions there is a command "convert MBR" within diskpart that will take you from GPT to MBR. Then reformat.

Re question 2: I don't think so. You can go from GPT to MBR and back and forth, but not without losing the partitions and therefore the data.

Why do you need GPT at all? The typical reason to use it is because you have a drive in excess of 2.2 TB. MBR can't recognize above 2.2, but GPT can.

ignatzatsonic said:

Re question 1: I don't think you can convert from GPT to MBR on a disk with partitions. You'd have to use something like a Windows installation disk and go to a command prompt and use the "diskpart" command. I think after you delete the partitions there is a command "convert MBR" within diskpart that will take you from GPT to MBR. Then reformat.


Re question 2: I don't think so. You can go from GPT to MBR and back and forth, but not without losing the partitions and therefore the data.

Why do you need GPT at all? The typical reason to use it is because you have a drive in excess of 2.2 TB. MBR can't recognize above 2.2, but GPT can.

Damn. Was hoping I could keep the data without a new motherboard.

As per the title, I didn't mean to make it GPT. It's only a 2TB drive, I meant to go with MBR, but wasn't paying close enough attention.

Any idea if I just get a new motherboard capable of GPT if it will work?

Well, if you get a new motherboard, you will likely have issues with the existing installation on the drive because that installation was done with the current motherboard---leaving aside the GPT/MBR issue. Not to mention that you may have Windows licensing issues if you have an OEM license. You can't willy-nilly swap motherboards under an OEM situation.

Somebody else may have another idea as I'm not expert on GPT/MBR issues. But I'd think easiest thing would be to back up your data to another drive and start over, deleting all partitions and going with MBR all the way.

ignatzatsonic said:

Well, if you get a new motherboard, you will likely have issues with the existing installation on the drive because that installation was done with the current motherboard---leaving aside the GPT/MBR issue. Not to mention that you may have Windows licensing issues if you have an OEM license. You can't willy-nilly swap motherboards under an OEM situation.

Somebody else may have another idea as I'm not expert on GPT/MBR issues. But I'd think easiest thing would be to back up your data to another drive and start over, deleting all partitions and going with MBR all the way.

Unfortunately backing up my data to another drive is not an option, as all the original data is on a now fried drive, the new one with the full system image won't boot because it's GPT, and I don't have another desktop to work with. Oh well. I'll give this a few days to see if someone else can provide a solution, then I'll mark it solved.