Windows 10: Windows 10 GPT/UEFI + Windows 7 boot menu

What I have:

• Windows 10 booting from GPT drive via UEFI.
• A partitioned MBR drive with two Windows 7 installations.
• Machine can boot into Windows 10, but not the Windows 7 installations.

What I'd like:

• A boot menu containing all three OSes.

Available tools:

• Win 7 and Windows 10 64 bit installation media, on both DVD and USB.
• AOMEI Partition Assistant Pro which can convert a disk from MBR to GPT and visa versa without losing data.

Complications/details:

I tried using EasyBCD, which claims to support Windows 10 and UEFI, but it broke my BCD such that I couldn't boot into any OS. Took me a full day of research, trial and error to get it booting in Windows 10 again. In the process, I may have screwed up the boot records for the Windows 7 installations.


My BIOS (new Asus motherboard) used to show all my installations, and it would let me boot directly into each of them via "Boot Override" function. Now it only shows the Windows 10 installation.


If I run `bootrec /ScanOs` it shows all the Windows installations. I've run `bootrec /RebuildBcd` and said "yes" to each OS, but the machine still boots directly into Windows 10.


I tried running recovery tools on the Windows 7 installation disk, and it tells me I can't because I have the wrong version of Windows (it's the same disk I used to install Windows 7, but it sees Windows 10 and refuses to let me continue).


I used bcdedit to add one of my Windows 7 partitions to the Windows Boot Manager:


Code: Windows Boot Manager -------------------- identifier {bootmgr} device partition=\Device\HarddiskVolume2 path \EFI\MICROSOFT\BOOT\BOOTMGFW.EFI description Windows Boot Manager locale en-us inherit {globalsettings} default {current} resumeobject {3efead84-5517-11e5-a453-d7730d7389bf} displayorder {current} {3efead86-5517-11e5-a453-d7730d7389bf} toolsdisplayorder {memdiag} timeout 5 Windows Boot Loader ------------------- identifier {current} device partition=C: path \Windows\system32\winload.efi description Windows 10 locale en-us inherit {bootloadersettings} isolatedcontext Yes allowedinmemorysettings 0x15000075 osdevice partition=C: systemroot \Windows resumeobject {3efead84-5517-11e5-a453-d7730d7389bf} nx OptIn bootmenupolicy Standard Windows Boot Loader ------------------- identifier {3efead86-5517-11e5-a453-d7730d7389bf} device partition=E: path \Windows\system32\winload.efi description Windows 7 DAW locale en-us inherit {bootloadersettings} isolatedcontext Yes allowedinmemorysettings 0x15000075 osdevice partition=E: systemroot \Windows resumeobject {3efead84-5517-11e5-a453-d7730d7389bf} nx OptIn bootmenupolicy Standard[/quote] This adds "Windows 7 DAW" to the Windows Boot Manager. When the disk containing Windows 7 was MBR, selecting that option just crashes the machine and causes a reboot. If I change that disk to GPT, it bluescreens saying \Windows\system32\winload.efi (or \Windows\system32\winload.exe; I tried both) is corrupt.

:)

 

Why do new laptops come installed with GPT formatted hard drives?

Hi,

Thank you for being part of Windows 10.

You get the GPT message when you boot into the Legacy version of the install media and try to install on a GPT (UEFI) configured drive. The install media has the ability to boot as UEFI or Legacy and depending on your system, needs to be chosen at boot
using a boot device menu. USB drives formatted as NTFS will not boot as UEFI.

Yes, you need an x64 version to be able to use UEFI of Windows 7, 8.1 or 10.

And as has been mentioned, GPT is the configuration for the Entire Drive, not just one partition.

Do get back to us for any issues pertaining in the future. We will be happy to help.

 

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.