Problems dual booting 2x Win10 & even 1x Win7 1x Win10

I'm no pro by the way guys so go easy :)

So for 10 years or so i have had 2 Windows 7 installs on a dual boot / multi boot and before that the same with XP. To save time we'll not get in to the whys and why nots. I appreciate it's not the usual dual boot setup, you usually have different OS. These were always on the same key.

So this week i went to do the exact same with Windows 10. No joy. Windows 10 installs but whichever partition is not the default, it restarts before booting to Windows. So say we have partitions for Bill & Ben. Bill is default.
You get to the dual boot screen, you press enter on Bill as the default & it accesses Windows. No problem. You then restart.
You get to the dual boot screen, drop down to access Ben's Windows 10 partition, the PC then restarts and once it goes through the motions it eventually accesses Windows 10 for Ben.

I tried ....

* Creating the second partition on the install page.
* Installing Windows 10 to the drive as 1 partition, accessing disk management once up and running, shrinking the volume and then installing to that new partition.
* Creating 2 partitions on the same physical drive
* Installing to 2 separate physical drives
* Disabling Fast Startup via the control panel: How to disable Windows 10 fast startup (and why you'd want to) | Windows Central
* Disabling Quick Start in my BIOS

I did a brand new install for each of those scenarios. I got the same result.

I think what may be helpful is that as said earlier, Bill is default. If i go in to msconfig or BCDEdit and switch it so that Ben is now the default partition and Bill is the one who is second then the problem partition changes. So...
before Bill would be default and boot no problem, Ben would be secondary and would restart.
...but if you change the default then Ben is now default and accesses Windows perfectly fine whereas Bill now restarts before accessing Windows.

So the issue to me doesn't seem to be with one specific partition, more about which one is not default.


So then i tried dual booting Windows 7 and Windows 10.....

* I install Windows 7.
* Once up and running i access disk management, shrink the volume. Restart
* Install Windows 10 to the new partition just created.

Windows 10 is now the default, right?
Windows 10 boots perfectly fine. Restart the PC to test Windows 7.
Get to the dual boot screen, drop down to select Windows 7 .... PC restarts itself before eventually loading Windows 7.


Really looking for some help on how to sort this problem out. And before anyone suggests it .... no thank you to a Virtual Machine. :)

Makes sense, @Kyhi. I always mistakenly attributed to it being the way UEFI works.

Another hint, Windows 10 fast startup can interfere with dual booting. I like to disable hibernation, so the hiberfil.sys file gets deleted, and that also disables Windows 10 fast startup:
powercfg -h off

Kyhi said:

What is happening is that since the installation of Windows 10 - It is using the Metro Boot Loader (Button Interface GUI).. So when your PC is booted it displays the Metro Loader - after Selecting the OS via the Button - It reboots into that OS...
You can do away with the seemingly Reboot - by turning off the Metro Boot Loader...

From an elevated command prompt type>

Code:

bcdedit /set {bootmgr} displaybootmenu True

This will give you the Black Screen with White Letters - Old Style Boot Menu

I've had it put to me that i didn't turn off fast startup when i did the 7 & 10 dual boot and this may be causing the problem. I'll try that out first and see if that's correct.

If not then i'll try your method and report back. Thanks for taking the time to reply, both of you.

- - - Updated - - -

Kyhi said:

What is happening is that since the installation of Windows 10 - It is using the Metro Boot Loader (Button Interface GUI).. So when your PC is booted it displays the Metro Loader - after Selecting the OS via the Button - It reboots into that OS...
You can do away with the seemingly Reboot - by turning off the Metro Boot Loader...

From an elevated command prompt type>

Code:

bcdedit /set {bootmgr} displaybootmenu True

This will give you the Black Screen with White Letters - Old Style Boot Menu

You sir are a diamond! I've tried so many variations and spent/wasted so many hours on this now that i was starting to give up. This worked a treat.

I don't know if it'll only work with Windows 7 & 10 as a dual boot or whether it'll also work for a 10 & 10 setup. At a push i can get away with a 7 & 10 so that'll do for me if 2 Windows 10s side by side don't work. Thank you again.

Do you do that on the black screen we've discussed or on the 'usual' Windows 10 boot screen?

If the latter then how did you manage it when i can't?

Sorry, i'll rephrase my previous post so that it's clearer. My bad.

Do you do that (boot 8.1 and both of the Windows 10 installs) using the black dual/multi boot screen or do you do it using the Windows 10 style boot screen?

If you have it on the Windows 10 style boot screen then how do you manage that? Since it appears to be causing me so much trouble.