Windows 10: Partition Prerequisites for converting to GPT using MBR2GPT

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  1. Posts : 59
    Win7 Home Premium & Win10 Pro in dual boot
       15 Nov 2017 #1

    Partition Prerequisites for converting to GPT using MBR2GPT


    Hi
    I am looking into converting from a BIOS based system to UEFI using MBR2GPT but I understand there are specific rules for the layout of the system disk. Currently I have four Primary partitions comprising System Reserved, Windows 7, Windows 10 and an unnamed partition which I believe to be the Recovery partition. Should I decide to go ahead then Windows 7 will come out but what of what is left?

    In searching out info before making my decision I found this site:


    Now I understand there have been a number of folks on this forum who have had problems because their partition layout before starting their conversion using MBR2GPT was incompatible with UEFI. Could I therefore ask Brink or someone else with knowledge on this topic to please give us some idea of the prerequisites re partitions (and indeed anything else) for the conversion including partition sizes since I understand the MSR partition MUST come between the System Reserved and Windows partitions as stated in the item above.

    Any help would be most appreciated.
    Tracey

    PS I include below my disk layout more specifically my System disk layout as of this moment for any comment but please bare in mind that Windows 7 will come out.

    Click image for larger version. 

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      My ComputerSystem Spec

  2.    15 Nov 2017 #2

    Hi, here's Brink's tutorial.
    Convert Windows 10 from Legacy BIOS to UEFI without Data Loss Installation Upgrade Tutorials
    But it looks as if you're dual booting, and the tutorial says
    If you dual boot Windows 10 with any other operating system, then do not use this tutorial. This tutorial is only meant for a standalone Windows 10 installation on a PC.
    Another:
    Convert MBR Disk to GPT Disk in Windows 10 Hardware Drivers Tutorials
      My ComputerSystem Spec

  3.    15 Nov 2017 #3

    The main issue is your boot drive already has four primary partitions and it looks like you are dual booting anyway.

    I recommend you back up all data on Windows 7 partition and remove it and the system reserved partition, then use mbr2gpt, then reinstall windows 7 from scratch (you will need to disable secure boot to install it in UEFI mode.
      My ComputerSystem Spec


  4. Posts : 59
    Win7 Home Premium & Win10 Pro in dual boot
    Thread Starter
       15 Nov 2017 #4

    Hi Guys

    Thanks for your replies but I don't think you've really read my post. If you read it carefully you will find that I have said that "Windows 7 will come out" and I also asked readers to bare this in mind. To put it another way, Windows 7 will be taken out before I try the conversion so I will therefore have only three Primary partitions when I try the conversion.

    All I am looking for is clarification of the prerequisites for doing the conversion but please, if you are going to make comments on my system disk layout, please be sure you read my post properly and if there is anything you are not sure about then ask, please!

    Tracey
      My ComputerSystem Spec

  5.    15 Nov 2017 #5

    I did, and given your comment, will leave you to it. Good luck!
      My ComputerSystem Spec

  6.    15 Nov 2017 #6

    After you delete the Windows 7 partition, make sure you also delete the boot entry for it from the BCD. (bcdedit commands). Then give the MBR2GPT command a try. Keep in mind whenever you do anything like this there is always a chance you will lose everything, especially on the drive being modified, so I would make sure to have a backup created of whatever you cannot afford to lose.

    I believe the first thing MBR2GPT is going to do is verify the disk layout is acceptable to it for conversion and it will just tell if it isn't before it does anything.
      My ComputerSystem Spec


  7. Posts : 59
    Win7 Home Premium & Win10 Pro in dual boot
    Thread Starter
       16 Nov 2017 #7

    Hi

    Thanks for your replies. Dalchina sorry for my comments. Having had another look at my post I guess I could have made it absolutely clear by adding "before conversion". Sincerest apologies for my attitude and my omission.

    I have anyway found another reason not to do the conversion, at least not yet. This is that I do NOT have a UEFI enabled graphic card as I'm still using a GTX260 which is several years old and was produced before UEFI was adopted. In addition, having had a look last night, it seems I do NOT have the option to disable Secure Boot. As a result to do what I want I have to get a UEFI enabled graphic card, at least that is my understanding anyway. We'll see what turns up on Black Friday -- unless anyone here knows of any way I should be able to do it with a GTX260 but bare in mind my comment re Secure Boot.

    Tracey
      My ComputerSystem Spec

  •    16 Nov 2017 #8

    Another question becomes exactly why you were wanting to enable UEFI booting anyway? What did you want to accomplish with it? The biggest advantage to UEFI booting is the ability to boot a GPT partitioned drive to enable more than 4 primary partitions on it. Was that your goal, to have more than 4 primary partitions?
      My ComputerSystem Spec


  • Posts : 59
    Win7 Home Premium & Win10 Pro in dual boot
    Thread Starter
       16 Nov 2017 #9

    Hi

    I realise you can have more than four primary partitions but I've been told it goes a bit further than that. I understand that you also have enhanced security and an increase in booting and shutting down speed (not that either of them are important to me). You know, I'm now asking myself if the enhanced security is in itself enough reason to move to UEFI and is it likely to cause more trouble getting it up and running than it is worth. At present my PC works fine in BIOS mode and my old GTX260 does everything I want it to so do I really need to convert to UEFI. What do you reckon?

    Tracey
      My ComputerSystem Spec

  •    16 Nov 2017 #10

    TraceyW said: View Post
    Hi

    Thanks for your replies. Dalchina sorry for my comments. Having had another look at my post I guess I could have made it absolutely clear by adding "before conversion". Sincerest apologies for my attitude and my omission.

    I have anyway found another reason not to do the conversion, at least not yet. This is that I do NOT have a UEFI enabled graphic card as I'm still using a GTX260 which is several years old and was produced before UEFI was adopted. In addition, having had a look last night, it seems I do NOT have the option to disable Secure Boot. As a result to do what I want I have to get a UEFI enabled graphic card, at least that is my understanding anyway. We'll see what turns up on Black Friday -- unless anyone here knows of any way I should be able to do it with a GTX260 but bare in mind my comment re Secure Boot.

    Tracey
    Well done for apologising. People here bend over backwards to help.

    I am confused by your post. Do you mean a UEFI enabled motherboard, not graphic card.

    The graphic card has nothing to do with whether pc uses legacy bios or UEFI.

    Tell us what exactly you are trying to do and why?
      My ComputerSystem Spec


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