Windows 10: UEFI with MBR: Can I upgrade from Windows 7 to 10?

My Windows 7 Pro pc had BIOS on the motherboard, MBR on the 120GB SSD boot disk, and GPT on the 3TB HDD data disk. I was running out of room on the boot disk (and it was developing bad sectors) so I decided to switch it to a HDD with plenty of room (yes, SSD back to HDD.) So I cloned the boot disk to a new 3TB HDD. Of course since it's MBR, I can't access the entire disk. I also upgraded the mobo from BIOS to UEFI. So now I have these specs:


Motherboard: Gigabyte GA-Z68X-UD3H-B3 Rev 1.0 with UEFI
Boot disk: 3TB MBR HDD with MBR
Data disk: 3TB HDD HDD with GPT
OS: Windows 7 Pro


I'm considering an upgrade-in-place to Windows 10. The Windows 10 "assistant" says my pc is "good to go" but I'm concerned because it's UEFI with an MBR boot disk. Moreoever, I can't make use of the entire boot disk right now. I'm not sure how best to proceed.


- Can I upgrade from Windows 7 to 10 as things are now, with UEFI on the mobo and MBR on the boot drive?
- Are there good third-party tools to convert my boot drive from MBR to GPT without data loss?
- Am I better off flashing the mobo back to the its old BIOS? (And just not using the entire boot drive.)
- Is it worth investing in a larger SSD to use as an MBR boot drive? And just using the 3TB HDD as expansion space.
- Is upgrading in place my several years old Windows 7 install a bad idea in the first place? (Should I just stick with 7 anyway?)


Thanks for you thoughts.

:)

 

How to upgrade Windows 7 MBR installation on an UEFI motherboard

EDITED after working out how to run Windows 7 64-bit on a UEFI computer with GPT drive:

I don't know of a way to make Windows 7 work on a GPT drive. I have tried. If you do not have UEFI enabled you can't access the GPT disk properly. Also, you can only convert from an MBR to a GPT disk with a blank disk (no partitions) meaning
everything would need to be backed-up and restored (EDIT: unless using 3rd party tools such as Ubuntu and Gparted). Windows 7 also requires some Compatibility settings in UEFI to work if UEFI is enabled. I think this prevents some of the UEFI features, such
as Secure Boot, from working.

I also have a fully UEFI computer that shipped with Windows 7. I had upgraded it to Windows 8 shortly after purchase, so I switched to a GPT-initialized disk back then.

Do you have a setting that disables UEFI BIOS mode? If you can get Windows 10 to ignore the UEFI capability, that might work, at least until you accomplish the upgrade.

I have been able to dual-boot Windows 7 and 10 on a Legacy BIOS mode laptop,
but not on my newer UEFI Desktop PC. I might give it another try and see if there is a workaround, but I think for me using Secure Boot in UEFI with Windows 10 prevents Windows 7 from booting. <-- EDIT: disabling secure boot and enabling CSM made it
work.

Windows and GPT FAQ - Windows 10 hardware dev

From above article:

Can Windows 7, Windows Vista, and Windows Server 2008 read, write, and boot from GPT disks?
Yes, all versions can use GPT partitioned disks for data. Booting is only supported for 64-bit editions on UEFI-based systems.

What about mixing and matching GPT and MBR disks on the same system?

GPT and MBR disks can be mixed on systems that support GPT, as described earlier. However, you must be aware of the following restrictions:

• Systems that support UEFI require that boot partition must reside on a GPT disk. Other hard disks can be either MBR or GPT.
• Both MBR and GPT disks can be present in a single dynamic disk group. Volume sets can span both MBR and GPT disks.

 

Windows 10 clean install will not activate

My main desktop shipped with Windows 7 shortly before Windows 8 was released. It is fully UEFI and Secure Boot capable, but enabling that prevents reinstall of Windows 7, which requires an MBR-initialized disk (UEFI requires a GPT-initialized disk). I
upgraded to Windows 8 when it came out and installed a GPT-initialized SSD for my boot disk at the same time. I did not realize that my ability to boot Windows 7 was lost in the process, but I learned that I just can't boot Windows 7 on this device without
re-initializing the SSD to MBR.

If your computer only has Legacy BIOS mode, it makes things simpler, but it seems that when Windows 10 detects a UEFI-capable device it defaults to trying to set the computer up with a GPT partitioning scheme. That requires removing all drive partitions
to convert the drive to GPT and prevents Windows 7 reinstallation without first undoing all of that and disabling UEFI to convert the disk to MBR. To go back to Windows 7 then requires a clean install after making BIOS and disk changes.

Not sure if this is your situation too, but it sounds like a possibility.

So if your goal is Windows 10 on a UEFI computer that currently does not have Windows 7 installed, you would have to:

• disable UEFI (or enable compatibility mode to allow Windows 7 install)
• convert the disk to MBR
• reinstall and activate Windows 7
• upgrade to Windows 10, which should auto-activate
• then enable full UEFI and Secure Boot
• wipe the disk of all partitions, so that it can be initialized as GPT
• clean install Windows 10 (which should auto-activate)

 

If it was my computer, I would use Macrium Reflect Free to make a backup image of the current Windows 7 to the other 3TB HDD. Then I would make myself a Windows 10 USB installation drive (or DVD):
USB Flash Drive - Create to Install Windows 10 - Windows 10 Forums

Then I would capture the genuineticket.xml file using this procedure and save that to the other 3TB HDD:
Clean Install Windows 10 Directly without having to Upgrade First - Windows 10 Forums

Disconnect the 3TB drive that is GPT which now contains the backup image and the genuineticket.xml file. Make sure the MBR 3 TB hard drive is on the first sata port on the motherboard (Sata 0 or Sata 1 depending on how it is numbered). Boot the computer from the Windows 10 USB in UEFI mode. Once it boots and gets to the first screen, press Shift + F10 to get a command prompt. Run these commands:

diskpart
list disk (the 3TB MBR disk should be disk 0)
select disk 0 (or whatever disk number the 3TB MBR disk is)
clean
convert gpt
exit
exit

Then go on with the Windows 10 install. You will want to select the custom install option. You will want to pick the great big unallocated space to install to. Do not create any new partitions. Install the same version as your Windows 7 was. Click I don't have a product key when asked. A couple of more times you will be asked for a product key, click "skip" or "do this later". Let Windows 10 setup finish, create yourself a user account. Shut down computer.

Reconnect the 3TB GPT hard drive, reboot. Make sure the BIOS is set to boot from the 3TB hard drive you installed Windows 10 to. Copy over the genuineticket.xml file to the proper folder to activate the new Windows 10. Install Macrium Reflect Free again. Use it to browse the image file you created to copy back your data files. Re-install your programs/apps.