How to remove one of the hard drives in a dual boot setup with Win7 & 10


New Member
Hello. I was using EasyBCD 2.3 free and I ran into problems when I wanted to remove one of the hard drives. I had 2 hard drives on a computer: on one was Windows 7 and the other Windows 10. I needed to delete Windows 7 hard drive and use the hard drive for another project on another computer and keep windows 10 for that computer but I kept getting a message that the computer could not find the boot device when I removed the Windows 7 hard drive., even though Windows 10 remained. I installed EasyBCD 2.3 on the Windows 10 hard drive to delete the Windows 7 boot. Since I completely screwed everything, I was wondering what you are supposed to do to get rid of one of the operating system on an installed drive. I decided to do a BCD repair to start over for the Dual boot but now I can't even boot on Windows 10. So I gave up and decided to just reinstall Windows 10 again, since I see no way to get it to boot, unless someone has a suggestion. I would like for the future to know how to safely remove one of the hard drives in a dual boot setup. Any advice apreciated.


Knows where his towel is.
Staff member
When you install a new Windows with an existing Windows, Setup will automatically dual-boot the two by placing all the newer level of boot files in the "active" partition which will be the partition marked "system" on the original Windows disk.
That's why you can't remove the old OS because it's the only way of booting the PC.
EasyBCD can fix it for you
by copying everything necessary from the drive you wish to remove onto the newer disk.
Once you've done the above and rebooted and the old HDD no longer contains "system" and "active" flags, you can remove it.

Disk Management flags have the following meanings

"boot" = "this is the system you're running"
"system" = "this is where I found the boot files for the currently running system"
"active" (on the first HDD in the BIOS boot sequence) = "this is where I started the search for the boot files"
"active" (on subsequent HDDs in the BIOS boot sequence) ="this is where I will look if I don't find something in the MBR on the first HDD"