1

I am currently using Windows 7 and want to install Windows 10 in a dual boot configuration.

My Windows 7 disk uses MBR. My Asus motherboard bios shows

  • CSM: enabled
  • Boot Device Control: UEFI and Legacy OPROM

When I went to install Windows 10, I partitioned the existing (single partition) boot disk into two partitions and selected the second empty partition for Windows 10 but got the error:

"Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI system, Windows can only be installed to GPT disks."

So I figured I'd use a different drive for Windows 10 and set it to GPT. Before I do this I want to make sure I will get the dual boot scenario I'm hoping for.

Can I dual boot with Windows 7 on a MBR disk and Windows 10 on a GPT disk?

I'm not real clear where the master boot table resides and when the computer boots if it can read both disks (one MBR and one GPT) and present to me the choice of which OS to boot to. I am also not positive what it means to be using UEFI and Legacy.

Under Boot Device Control, my bios gives me the options

  • UEFI and Legacy OPROM
  • Legacy OPROM only
  • UEFI only

My goal is eventually to delete Windows 7, but this could take awhile as I configure Windows 10 to my satisfaction. Once I delete Windows 7, it would be nice to end up with the more modern GPT system on UEFI. Note, I have other legacy drives that use MBR that ideally I will continue to use. But, if necessary, I could go all GPT.

Thanks in advance for your help

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  • Anything you might need to run will run in Windows 10 (I have been using it for 5 years). Just leave Windows 7 behind, install Windows 10, answer mostly NO to the first setup screen after initial login, use a Microsoft Account if this is your personal machine (not on a domain) and then complete your setup while it is running and working for you – John Jan 19 '20 at 3:25
  • Thanks John, but I have hundreds of hours of installation and configuration necessary and not the time to devote to doing it all at once. As a developer with lots of interests, the number of tools to reinstall is a bit mind numbing. – mseifert Jan 19 '20 at 3:31
  • "Can I dual boot with Windows 7 on a MBR disk and Windows 10 on a GPT disk?" - No. MBR means Legacy mode only; GPT means UEFI only. You cannot do what you want. – Ramhound Jan 19 '20 at 3:42
  • @Ramhound - Based on what you've said, It looks like I'd have to use an MBR disk and disable UEFI on the motherboard (Legacy Only). The EasyBCD website says you can do this successfully using "Easy Recovery Essentials which can convert your existing installation to be bootable in both UEFI/GPT and BIOS/MBR mode in-place." It seems that this might then allow Windows 10 to be installed on an MBR disk - but then I'm left in legacy mode for the future with Windows 10. Bummer. Strange that Windows 7 can be installed with an MBR disk but WIndows 10 cannot on this machine. – mseifert Jan 19 '20 at 4:05
  • 1
    The last time I used EasyBCD it broke my installation. Windows 10 can already be installed on an MBR disk. You don't have to do anything special to do that. Especially use EasyBCD which is shovelware. Who told you that Windows 10 doesn't support MBR? – Ramhound Jan 19 '20 at 4:07
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It is possible to install Windows 7 to BIOS boot on your computer. Therefore, you could also install two Windows 7 operating systems in a dual boot configuration. Again, both would BIOS boot. I assume then that you could also upgrade the second Windows 7 to Windows 10. Again, Windows 10 would BIOS boot. When you boot the computer, a menu will appear which will allow you to select which windows you want to use. So you do not have to use a BIOS Windows 7 and UEFI Windows 10 combination.

The 64 bit Windows 10 installation media contains both the files to BIOS and UEFI boot. If you BIOS boot from the installation media, then the GUI will require the installation drive to be partitioned using the Master Boot Record (MBR) partition table. Windows will be installed to BIOS boot. Similarly, if you UEFI boot from the installation media, then the GUI will require the installation drive to be partitioned using the GUID Partition Table (GPT). Windows will be installed to UEFI boot.

You can also boot from the Windows 7 or 10 installation media, open a Command Prompt window, then issue commands to install Windows. This is one way to BIOS boot from the media, then install Windows to UEFI boot. The reverse is also true. (i.e. UEFI boot and BIOS install) However, installing from the command line is rarely needed.

Legacy Mac computers also allowed for hybrid partitioning where both the MBR partition table and GPT were used to install operating systems. In this case, you could install Windows to BIOS boot and also have other operating systems (such as macOS and Linux) UEFI boot. It is because of this that Windows 7 can not be installed to BIOS boot and have Windows 10 also installed to UEFI boot. In other words, once you setup a hybrid arrangement both Windows 7 and 10 have to be installed to BIOS boot.

Install a Dual Boot from a Command Prompt Window

A free product named VirtualBox was used to illustrate and test the procedure.

Here is how VirtualBox version 6.0.14 r133895 (Qt5.6.3) was setup. The Name, Type and Version where chosen as shown below.

Note: The host computer is an Apple iMac (21.5-inch, Mid 2011).

Since the host computer has 16 GB of memory, the virtual machine was set to have 4096 MB of Base Memory. Also, to EFI boot Enable EFI (special Ones only) was checked off. See below for an illustration.

Since the host has 4 cores, the Processor(s) was set to 2 CPUs. Also, Enable PAE/NX was checked off. See below for an illustration.

Finally, a second SATA internal drive was added, as shown below.

The current Windows 10 and Windows 7 iso files were downloaded from Microsoft. The iso files were virtually inserted in the virtual machine DVD drive starting with the Windows 10 iso. Physical iso files were used to install Windows. However, physical flash drives can be substituted without significantly changing the steps shown below.

After UEFI booting from the virtual DVD drive containing the Windows 10 iso, the following window was displayed.

Entering the key combination shift+F10 will open a Command Prompt window, as shown below.

The following commands were entered to install Windows 7 to BIOS boot on disk 0 and Windows 10 to UEFI boot on disk 1. Be aware, there is a comment where you need to swap the Windows 7 DVD for the Windows 10 DVD.

Note: In the commands shown below, you may have to substitute install.esd for install.wim.

Microsoft Windows [Version 10.0.18362.418]
(c) 2019 Microsoft Corporation. All rights reserved.

X:\Sources>diskpart

Microsoft DiskPart version 10.0.18362.1

Copyright (C) Microsoft Corporation.
On computer: MINWINPC

DISKPART> select disk 0

Disk 0 is now the selected disk.

DISKPART> clean

DiskPart succeeded in cleaning the disk.

DISKPART> create partition primary

DiskPart succeeded in creating the specified partition.

DISKPART> format fs=ntfs label=Windows7 quick

  100 percent completed

DiskPart successfully formatted the volume.

DISKPART> active

DiskPart marked the current partition as active.

DISKPART> assign letter=c

DiskPart successfully assigned the drive letter or mount point.

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> clean

DiskPart succeeded in cleaning the disk.

DISKPART> convert gpt

DiskPart successfully converted the selected disk to GPT format.

DISKPART> create partition efi size=300

DiskPart succeeded in creating the specified partition.

DISKPART> format fs=fat32 label=EFI quick

  100 percent completed

DiskPart successfully formatted the volume.

DISKPART> assign letter=s

DiskPart successfully assigned the drive letter or mount point.

DISKPART> create partition msr size=16

DiskPart succeeded in creating the specified partition.

DISKPART> create partition primary

DiskPart succeeded in creating the specified partition.

DISKPART> format fs=ntfs label=Windows10 quick

  100 percent completed

DiskPart successfully formatted the volume.

DISKPART> assign letter=w

DiskPart successfully assigned the drive letter or mount point.

DISKPART> exit

Leaving DiskPart...

X:\Sources>dism /get-imageinfo /imagefile:d:\sources\install.wim

Deployment Image Servicing and Management tool
Version: 10.0.18362.1

Details for image : d:\sources\install.wim

Index : 1
Name : Windows 10 Home
Description : Windows 10 Home
Size : 14,513,453,277 bytes

Index : 2
Name : Windows 10 Home N
Description : Windows 10 Home N
Size : 13,698,165,844 bytes

Index : 3
Name : Windows 10 Home Single Language
Description : Windows 10 Home Single Language
Size : 14,495,067,516 bytes

Index : 4
Name : Windows 10 Education
Description : Windows 10 Education
Size : 14,780,689,298 bytes

Index : 5
Name : Windows 10 Education N
Description : Windows 10 Education N
Size : 13,967,235,459 bytes

Index : 6
Name : Windows 10 Pro
Description : Windows 10 Pro
Size : 14,782,181,615 bytes

Index : 7
Name : Windows 10 Pro N
Description : Windows 10 Pro N
Size : 13,968,715,159 bytes

Index : 8
Name : Windows 10 Pro Education
Description : Windows 10 Pro Education
Size : 14,780,619,060 bytes

Index : 9
Name : Windows 10 Pro Education N
Description : Windows 10 Pro Education N
Size : 13,967,164,321 bytes

Index : 10
Name : Windows 10 Pro for Workstations
Description : Windows 10 Pro for Workstations
Size : 14,780,653,945 bytes

Index : 11
Name : Windows 10 Pro N for Workstations
Description : Windows 10 Pro N for Workstations
Size : 13,967,199,656 bytes

The operation completed successfully.

X:\Sources>dism /apply-image /imagefile:d:\sources\install.wim /index:6 /applydir:w:\ /checkintegrity

Deployment Image Servicing and Management tool
Version: 10.0.18362.1

Applying image
[==========================100.0%==========================]
The operation completed successfully.

X:\Sources>rem Removed Windows 10 DVD and inserted Windows 7 DVD.

X:\Sources>dism /get-imageinfo /imagefile:d:\sources\install.wim

Deployment Image Servicing and Management tool
Version: 10.0.18362.1

Details for image : d:\sources\install.wim

Index : 1
Name : Windows 7 Home Basic
Description : Windows 7 Home Basic
Size : 11,710,161,360 bytes

Index : 2
Name : Windows 7 Home Premium
Description : Windows 7 Home Premium
Size : 12,222,587,449 bytes

Index : 3
Name : Windows 7 Professional
Description : Windows 7 Professional
Size : 12,122,886,417 bytes

Index : 4
Name : Windows 7 Ultimate
Description : Windows 7 Ultimate
Size : 12,285,492,779 bytes

The operation completed successfully.

X:\Sources>dism /apply-image /imagefile:d:\sources\install.wim /index:3 /applydir:c:\ /checkintegrity

Deployment Image Servicing and Management tool
Version: 10.0.18362.1

Applying image
[==========================100.0%==========================]
The operation completed successfully.

X:\Sources>bcdboot c:\windows /l en-us /s c: /f bios
Boot files successfully created.

X:\sources>bcdboot w:\windows /l en-us /s s: /f uefi
Boot files successfully created.

X:\sources>bootsect /nt60 c: /mbr
Target volumes will be updated with BOOTMGR compatible bootcode.

C: (\\?\Volume{02cca004-0000-0000-0000-100000000000})

    Successfully updated NTFS filesystem bootcode.

\??\PhysicalDrive0

    Successfully updated disk bootcode.

Bootcode was successfully updated on all targeted volumes.

X:\sources>exit

Remove the DVD and click on the the red X to restart the virtual machine. Finish installing Windows 10. Shutdown the virtual machine then uncheck the Enable EFI (special Ones only) option in the setup, as shown below.

BIOS boot the virtual machine and finish installing Windows 7.

Optional Steps

The following was omitted in the above example.

  • The System and Recovery partitions were omitted from disk 0. The files that would have been stored in these partitions were installed in Windows partition of disk 0 instead.
  • The Recovery partition was omitted from disk 1. The files that would have been stored in this partition were installed in Windows partition on disk 1 instead.
  • Any extra steps needed to install for Secure Boot.
  • The use of the Dism /Add-Driver command to add any required drivers to the driver store.

Additional References

DISM Image Management Command-Line Options
DISM Driver Servicing (.inf) Command-Line Options
BCDBoot Command-Line Options
Bootsect Command-Line Options
BIOS/MBR-based hard drive partitions
UEFI/GPT-based hard drive partitions

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  • Something about having the boot mode set to UEFI and Legacy - when booting into the Windows 10 Install disk, the installation probably detected UEFI. I think I could set the motherboard to Legacy Only and Win 10 should install. Installing Windows 7 and then doing an upgrade is a good thought, but probably the long way to do it. At this point, I'm considering shelving this Windows 10 install for awhile, perhaps until I need a new rig and all the effort to upgrade will really be worth it. – mseifert Jan 20 '20 at 2:00
  • I tried to update my answer to explain why you received the error message marked in yellow in your question. – David Anderson Jan 20 '20 at 2:39
  • The issue is how to know which method the Install disk is booting with or more precisely, which mode it thinks is being used for the new Windows 10. I now know it thought I was using UEFI. I'd love to know how to (with this UEFI boot) do a BIOS install from the command line. It would be an alternative to changing my motherboard settings, which would be preferable for me. If you could include a link to that info (or the instructions), I'd call that the answer and be done with the thread (and select your answer as correct to boot - please excuse the pun). – mseifert Jan 20 '20 at 3:22
  • Ok, I added to my answer an example of how to do what you asked in your question. This was tested using a virtual machine created using a free product called VirtualBox. Commands were entered in to a Command Prompt window instead of using the GUI installer. This allowed a BIOS booting Windows 7 and an UEFI booting Windows 10 to be installed on separated drives. – David Anderson Jan 20 '20 at 19:17
  • Wow. I I didn't expect such a thorough answer. Well done. Thanks. I've got some reading to do. – mseifert Jan 20 '20 at 23:20

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