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How to Convert MBR to GPT Safely for Dual Booting?


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15 replies to this topic

#1 john1816

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Posted 24 February 2018 - 09:18 PM

Hi all, this is the first time I'll be doing this so bare with me for my limited knowledge. 

 

I am looking for a way to convert my drive from MBR to GPT safely which will be my first time trying to do. I need to do this because I want to have both Windows 10 and a Linux Distribution to dual boot. I currently have a single MBR drive on my laptop on Windows 10 from where I am booting from (I only have 1 1TB drive on my laptop). I have been trying to install the Linux distribution via BIOS mode to the MBR drive for a couple of hours but it does not work (made a bootable USB via rufus program, set it to FAT32 and yes, - I didn't just copy/paste the ISO file onto the USB :P), it keeps booting back to Windows 10 after I clicked on "install" when I reached the screen to install the OS, which leads me to the conclusion that I could only install it via UEFI mode (unless I have done something wrong or I missed a step). UEFI however, has to boot from a GPT drive for it to work which then leads me the need of converting my single MBR drive of my laptop to GPT. 

 

The Linux distribution apparently can only be installed in UEFI mode and there are some issues of trying to make UEFI work with MBR drives: https://www.rodsbooks.com/gdisk/bios.html Essentially if i could have both operating systems installed on the converted GPT drive, I would be able to dual boot either of them without any issues via UEFI mode setting. 

 

There are some articles in the net saying you can convert MBR to GPT drives straight away without any data loss by running some commands on disk part or using a software to do it for you without any precautions listed.

 

However, I have also read some precautions like you should not convert your boot drive from MBR to GPT which is why I am not sure how to go about this way or do not convert your MBR to GPT drive if it has partitions (which I do). The other option for me is to just format the drive as GPT and reinstall Windows 10. 

 

So how should I convert my MBR to GPT drive safely?


Edited by john1816, 24 February 2018 - 09:29 PM.


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#2 jenae

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Posted 24 February 2018 - 11:16 PM

Hi, good article from MS:-

 

https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt



#3 Rocky Bennett

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Posted 25 February 2018 - 10:26 AM

This is a very educational thread but I have been multi-booting Windows 10 and several different Linux distros on my Haswell based PC for years using the MBR partition scheme. Right now I have Windows 10 installed on an MBR hard drive and Manjaro installed on a GPT hard drive. It has never caused me any concerns, issues or slow downs. My system is Asus Z 97 A motherboard, 4th gen Intel I5 4690 with a bunch of Crucial SSDs.


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#4 Gary R

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Posted 25 February 2018 - 11:48 AM

Converting from MBR to GPT is not entirely without risk, and it's possible that your hardware might not support GPT.

 

If all you're wanting to do is dual boot Windows and Linux, then there should be no reason at all why you can't do that on a MBR formatted disk.

 

If you're having trouble installing Linux, then I suggest you open a topic in our Linux forum ... https://www.bleepingcomputer.com/forums/f/11/linux-unix/ ... and the experts there should be able to help you out.



#5 Rocky Bennett

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Posted 25 February 2018 - 01:07 PM

I agree with Gary R. Before I was able to afford several SSDs for my system, I was dual booting Windows 10 and a couple of different Linux distros on one MBR partitioned drive. It never caused me any problems.


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#6 JohnC_21

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Posted 25 February 2018 - 01:23 PM

You have to determine why your drive was MBR to begin with. If you booted MBR then your computer either had a Legacy BIOS or your UEFI setting was set to Legacy or CSM boot. GPT disks do not play well with a Legacy BIOS.

 

But, I do believe that some UEFI MBs can autodetect whether a drive is MBR or GPT and boot accordingly. I may be wrong on that though.


Edited by JohnC_21, 25 February 2018 - 01:26 PM.


#7 Rocky Bennett

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Posted 25 February 2018 - 02:34 PM

You have to determine why your drive was MBR to begin with. If you booted MBR then your computer either had a Legacy BIOS or your UEFI setting was set to Legacy or CSM boot. GPT disks do not play well with a Legacy BIOS.

 

But, I do believe that some UEFI MBs can autodetect whether a drive is MBR or GPT and boot accordingly. I may be wrong on that though.

 

 

My Asus Z 97 is able to do this and that is why I now run a hybrid system; one OS on a GPT drive and one OS on an MBR drive.


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#8 heyyou325

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Posted 25 February 2018 - 06:31 PM

I have been dual booting Windows, with Mint and Zorin (they needed to have a uefi key) for years also as Rocky and Gary both have.  I'm not hijacking this thread, but last Oct, with the big update, I haven't been able to duel boot anymore.  Same with using live boot, either usb, nor dvd.   I figured it was something in the  fall update, and saw other threads about it too.  I saw this thread and thought I'd follow it lurking to see if it helped me.  When I get some time I think I'll try that info from Jenae above.  I just cleaned an old windows 7 laptop to convert the whole thing to Linux, but I like being able to duel boot.  I'm gonna lurk here some more to see what follows.



#9 john1816

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Posted 25 February 2018 - 10:54 PM

Thanks for the replies

 

I installed my windows 10 on my laptop via Legacy mode (BIOS) when I popped in my USB for it hence my drive became MBR. Windows 10 still supports Legacy actually. However now that I think of it, I may have gotten an Iso file that can only work with UEFI rather than Legacy bios. The Linux distro that I'm trying to install should work on EITHER BIOS or UEFI modes. I'll try downloading another iso file again and see if it helps. My laptop also has an option to boot via UEFI mode so I guess it can handle UEFI. 

 

@heyyou325

Yes the problem is, Windows 10 has automatic updates that you cannot disable (i am not sure if disabling the update service in services.msc will stop the windows update service completely but what that does is that it stops the update service). Whenever it updates, it may screw up with the windows boot loader which is what loads windows 10 and is stored usually in the system reserve if you look at cmd>diskmgmt. This is another issue that I will also have to deal with once I get to install Linux. https://unix.stackexchange.com/questions/68581/how-can-i-prevent-windows-from-overwriting-grub-when-using-a-dual-boot-machine. Windows can replace the Linux Grub loader when booting the machine, preventing you to boot to the other OS. But basically from what I've read from other forums, its advised to install Windows first then Linux. 

 

*If any of you whom have already been able to Dual boot windows 10 and Linux, have you guys found a way to prevent this from happening after every Windows 10 update?


Edited by john1816, 25 February 2018 - 11:00 PM.


#10 Gary R

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Posted 26 February 2018 - 01:35 AM

Personally on my W10 machine I run Linux in a VM, and that removes any incompatibility problems that might be caused by W10's "forced" updates.

 

It would of course also remove any potential problems with disk formatting or boot loaders.


Edited by Gary R, 26 February 2018 - 01:37 AM.


#11 heyyou325

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Posted 26 February 2018 - 12:59 PM

Thanks for the info John.  



#12 john1816

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Posted 04 March 2018 - 11:23 PM

Ok its been more than a week but I've managed to install Windows 10 in UEFI mode as GPT. I looked into gptgen and AOMEI tools to make the drive from MBR to GPT but they don't work for me for some reason, so I  had to reformat my laptop. Its not possible to make the drive from MBR to GPT while Windows is running as it is the active partition. I first changed the boot mode to UEFI and set the boot order to USB, downloaded a Windows 10 UEFI iso and put it on usb with rufus then plug it in to my laptop. Next, im gonna try to install the Linux distro now, hopefully it should work but before that I'll have to update windows first and then disable the windows update service.I checked my hard drive its installed as GPT in diskmgmt.

 

@ Gary R

Yes, a VM would eliminate that inconvenience but it makes running the Linux OS sluggish for me in my laptop as I've tried it. The Linux OS won't be able to fully utilize the laptop's hardware as it is limited by the VM and also there may be some compatibility issues. 


Edited by john1816, 04 March 2018 - 11:28 PM.


#13 Rocky Bennett

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Posted 05 March 2018 - 09:12 AM

You can change your C: drive from MBR to GPT while it is active,

 

https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt


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#14 john1816

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Posted 06 March 2018 - 02:35 AM

Ah, my bad i didn't see it could do that  :smash:  that would've saved me hours. Oh well but what's done is done. 

 

Just watched the whole video in that link. Interesting to note there is you can't really use that tool on a Windows 7 machine or older i guess, you can however convert windows 7 to windows 10 and then use that tool as mentioned in timestamp 3:38 in the video. I have a windows 7 desktop that's still on MBR but will upgrade its HDDs to greater than 2TB in the future. I don't plan to use windows 10 on it because of compatibility issues with some programs and the self-installed cortana spyware/forced windows updates that comes along with it. 



#15 IttechGyan

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Posted 06 March 2018 - 04:47 AM

AOMEI should convert MBR to GPT with just a few clicks, without data loss. Other methods such as DISKPART would erase data. Either way, I'd recommend backing up important data before making such a change.






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