Windows 10: How to Dual Boot Multiple HDD's

First and foremost to the Moderators if this isn't the right place I apologize. It seems right.

Here is what I have:

3 Internal HDD's: One is my main Windows 10 Installation and the other 2 are simple storage.

What I want:

Install Windows 7 to one of them and dual boot it with 10. I was hoping to avoid a total reinstall of Windows 10 by unplugging that and installing it to one of the blank HDD's I have. Then re-plugging Win10 back in and setting the main OS.

I am pretty sure I heard of this working before and I'd like to do it. If I REALLY wanted it I could reinstall both but damn....I don't want to.

Also my system is a UEFI type. (I am not entirely sure what that means but I know it has an impact on certain OS's)

:)

 

Dual boot windows 10

Can I dual boot windows 10 from two HDDs in the same PC rather than dual boot from same HDD and how? and will this not affects windows license and or activation?

 

2 HDD, 2 OS, current installation pattern not optimal, preliminary actions unsuccessful, proposed action, opinions sought, any better approach?

Dual Booting Explained: How You Can Have Multiple Operating
Systems on Your Computer

 

You are overcomplicating things. Simply install Windows 7 to one of blank drives, and dual boot will be setup with a menu at startup.

If you unplug the w10 hdd, it will not be dual boot as such, and you would have to select which drive to boot from bios.

Only minor issue is that if you install 7 after 10, you get the old style text boot menu rather than the new style graphic menu, but this is easy enough to fix using easybcd or bcdedit commands.

 

Well son of a bitch. That's what I did. I unplugged the win10 and installed 7 for two reasons:

1) I heard installing an old OS on a separate drive/partition will override the boot loader and cause it to not load anything at all

2) it wouldn't let me install windows with he other hdds installed for some reason.

So windows 7 is currently installed but when I have my windows 10 HDD in it auto loads windows 10 and doesn't let me select an OS. File explorer does detect the 7 drive and I can access the files but as of this moment I have to unplug the Win 10 HDD to load 7.

So is there anything I can do to fix this without reinstalling? If I have to reinstall I will its still a bare bones install.

 

The boot timeout may have defaulted to 0 seconds,
Hold Shift and press Restart to check the options.

 

Let's say in Windows 10, the Windows 7 partition is E: drive. In a Command Prompt (Admin) ("Run as Administrator" Command Prompt) run:

bcdboot E:\Windows /d /addlast

Change the drive in red to match what Windows 7 gets assigned in your Windows 10.

You can change the default OS and the timeout on the boot tab of MSCONFIG.

 

Wow! Thank you so much NavyLCDR!

Also a shout out to everyone else here who replied *Smile

 

Amazingly easy, eh?

 

It added Windows 7 to the OS list but I am going to reboot and see if it actually gives me the option before I celebrate. Will edit with the reply.

 

Oh ye of little faith!

 

Now we have a major problem. When I did this it booted right into Windows 7 when it usually goes to Windows 10 first and no menu for selecting an OS. In Windows 7 I can access the W10 drive on E:/ files and all but it will not boot into Win10. When it did Windows 7 insisted on a disk check for "Consistency" for the Win10 Drive. So I let it do it's thing then it did something I've never seen before

"Deleting extended attribute set due to the presence of reparse point in file XXXXXX" For hundreds of thousands of files.

[youtube]kyH_xBUy7XU[/youtube]

This went on for like 5 minutes so I got irritated and did something I probably shouldn't have done which was hit the rest button on my PC. I rebooted into Win7 again and skipped the checks. Got to my desktop and I could still access my Win10 drive. Windows 10 is also now gone from the OS list.

When I rebooted my PC I hit F11 for the boot menu and selected the Windows 10 Drive. It said something about inserting bootable media. I didn't take a screenshot of that. I plugged in my Windows 10 USB and booted from that and selected repair errors that prevent startup. It couldn't fix the errors so I chose to Recover using a restore point. It gave me an error box saying something like "Restart and select windows version you want to repair" Even after I unplugged my Windows 7 drive it still said this."

This all happened after I entered that command you told me to input. And yes Windows 7 happened to be E:/

So for a super short version:

I did that command in command prompt. Windows 7 DID list in the OS list on Windows 10. I rebooted and it went into Windows 7 immediately. Did a disk check stating "Deleting extended attribute set due to the presence of reparse point in file XXXXXX" Windows 7 can access the Windows 10 Files no problem in File Explorer. Cannot repair it with my USB Win10. Cannot boot into it or repair even with Windows 7 unplugged.

 

The command I had you entered is only supposed to add an entry to file that shows the Windows boot menu. I suspect there was some corruption in the Windows 10 file system and the bcdboot command writing to the bcd file must have triggered it. The computer could no longer read the Windows 10 boot files because of the file system corruption and fell back to the old boot files contained on the hard drive containing Windows 7. So let it boot into Windows 7. You don't have to do the next step, it is just a precaution, but I highly recommend it:

Create a bootable USB flash drive of Kyhi's Recovery Tools. This will have many utilities you can use to fix your system if it stops booting altogether:
Windows 10 Recovery Tools - Bootable Rescue Disk - Windows 10 Forums

The reliable way to make a bootable flash drive from the ISO file of Kyhi's Recovery Tools is:
Insert the flash drive with Windows running. It will be erased during this process. "Run as Administrator" Command Prompt. Run:
diskpart
list disk
select disk # <-replace # with the actual number of the flash drive
clean <- this will erase the disk selected above - make sure it is the USB flash drive!
create part pri
format fs=fat32 quick
active
assign
exit
exit

The flash drive should now have a drive letter. Mount the ISO file of Kyhi's Recovery Tools using a program such as WinCDEmu:
WinCDEmu - the easiest way to mount an ISO. And more...

Once you get the ISO file mounted, copy all the files and folders that appear to the USB flash drive. Then you can test booting to it to make sure you can get into Kyhi's Recovery Tools.

Set that aside for now. That's the end of the optional, recommended step.

In Windows 7 post a screenshot of disk management:
Disk Management - How to Post a Screenshot of Windows 10 General Tips Tutorials
Make sure to widen the columns so we can see all the data in the columns.

Now we are going to try to get back into Windows 10. If the bcdboot command messes up the Windows 7 boot files, we can use the screenshot of disk management and Kyhi's recovery tools to rebuild a boot partition, but the bcdboot command, by itself, should not break booting unless there is an underlying corruption somewhere else.

"Run as Administrator" Command Prompt again:
bcdboot E:\Windows

This time leave off /addlast /d. This should put Windows 10 at the top of the Windows boot menu and set it as the default OS to load. Reboot the computer, let it go into Windows 10. Also, change the drive letter if you have to to point to Windows 10.

If you get into Windows 10, open a command prompt (admin) and run the following command to turn off hibernation and delete the hiberfil.sys file, which can cause problems when dual booting with Windows 7:
powercfg -h off

Report back and let us know how all that went. Then we will work on rebuilding your boot partition on your primary drive.

 

A few quick things as I am at work right now.

1) I still have access to my Windows 10 HDD in Windows 7's file explorer so I've been backing my stuff up.

2) Since Windows 7 is running just fine can I simply reinstall Windows 10 and have it solve the dual boot issue? By that I mean finally giving me the option to select an OS on boot? Because I know you're supposed to install the older OS first.

If it will I might just go ahead and do that unless this is fixable. I already had backed up my files about a month ago so it's only a matter of getting a few more. I don't mind to reinstall if that's a guaranteed fix.

 

If you are looking for the easiest solution...
Unplug all the drives except the one you want Windows 10 on. Reinstall Windows 10. Open the Command Prompt (Admin) and turn off hibernation, which will also disable fast booting:
powercfg -h off

Shutdown by holding the shift key when you click shutdown from the power icon on the start menu (this will ensure you are doing a complete shutdown, not a "fast starup" shutdown).

Reconnect your other drives. Reboot into Windows 10.

Open Command Prompt (Admin) again. Run the BCDBOOT command again to add the Windows 7 to the boot menu:
bcdboot E:\Windows /d /addlast

Adjust the E: to match the drive letter assigned to the Windows 7.

That's the easy way to take care of all the problems.