Can't Dual Boot Windows 7 & 10

#1
I've installed multi-boot systems numerous times in the past and am somewhat familiar with EasyBCD. In the past to install a dual or triple-boot setup, I always just added the newest OS on the last unallocated partition and everything worked like a charm. (I boot up, see the options of the various OSes, and pick one for startup.)

Everything I've read online would suggest the Windows 10 Technical Preview worked the same way. But now that I have the full home version of Windows 10, it doesn't seem to work like that. I'm trying to install Windows 10 in addition to my existing install of Win7. Both are now on my computer- but I have to enter the BIOS each time when booting to select which drive to use!

So I added a Windows 10 option in the Win7 bootloader using EasyBCD - only if I select Windows 10 it just errors out with "0xc0000428 Windows cannot verify the digital signature of this file" and references windows\system32\winload.exe as the culprit.

I've tried both EasyBCD 2.2 and the 2.3 beta. Does anyone know what I'm doing wrong?
 

Terry60

Knows where his towel is.
Staff member
#2
You can't boot a newer Winload from an older Bootmgr.
Compatibility is backward, not forward.
Boot your W10 and add a W7 entry to the newer BCD.
Alternatively, if your W7 is on a faster device and you want to boot that way round for performance reasons, you'll need to rename W7's bootmgr and drag a copy of W10's (bigger) version across alongside it, so that the bootmgr will recognize the dig sig of Winload.
 
#3
I have tried booting from Windows 8.1 and adding a W7 entry to the newer BCD. The result is that when I select W7 from the boot menu, all I get is a dark screen with multi-color strip on top of the screen.
Following this advice, I renamed W7 winload.exe and then copied Winload from W8.1 to W7 \windows\system32 folder. There is no change in behavior. W8 gives error on winload.exe ans pressing escape brings up W8's BCD menu. Selecting W8 from there boots the machine.
 
#4
It looks like after I bypass the error, W8's boot menu is invoked. Is that normal if EasyBCD is installed on both disks? How do I fix the error screen if the above solution doesn't work?
 
#5
I'm new here, but haven't seen anybody use my technique, which is this:

Download a Windows 7 Recovery Disc. Easily, legally available on the web, from Microsoft, and you can find tips on how to use it.

Create it on a CD, and use it to boot. Then select the 'Repair' option.

It finds all of the viable boot partitions on your PC and sets-up a valid MBR.

Use EasyBCD to tweak it. It's simple, and usually works.
 

Terry60

Knows where his towel is.
Staff member
#6
But if you used it to repair a BCD and bootmgr created by W8, you will have back-leveled the modules.
What sizes are the two bootmgrs ?