Issue Dual-Booting and Installing 2nd Windows 10


I have been running Windows 10 on a desktop I built using a 120GB SSD. PC running great but needed more space. Had an extra HDD (750GB) from a Toshiba laptop. Wiped, formatted, bought W10 key, and installed as secondary drive. To be clear I know have one PC tower with 2 drives that each have windows installed on them. Every time I reboot my PC I am prompted to which Windows volume I want to boot in to. My PC ran great for a week but the 750GB HDD was noticeably slower than when I booted into the SSD windows volume (obviously). Two days ago I saw a deal on Amazon for a 250GB SSD so I grabbed it. Pulled out old HDD, Cloned it using Paragon Drive Copy and installed it. Cloning must not have worked properly so after a few hours of trouble shooting I figured it was best to just do fresh install. Wipe new SSD and format to NTFS, plug drive in, and plug in Windows Media Creation Tool. Go thru steps of installing and Windows comes up blah blah the usual. I go to reboot my PC and I am no longer able to boot into disk-0 (120GB SSD) only can boot into the drive I just installed. Restart and no more being prompted which Windows10 I want to boot into. Upon further research I believe the problem may be, everytime I install the second drive it hides the 99MB FAT32 Partition Volume. Notice, Disk-0 is missing Boot, Page file, and Crash dump. I have wiped both drives about 3 times each now and each time I cant boot other drive. Does anyone have a fix for this?

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Active Member
I have never had a reason to have two installs of Windows 10 on one computer. There is bound to be someone smart that will come along...:)


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Two things here:

Go to Search -> View advanced system settings then go to Advanced -> Startup and Recovery


Under Default Operating System do two copies of Windows 10 show or not?

Also please run msconfig.msc or Search -> System Configuration


^ You should see two operating systems here.

If not, there is a problem with the bootloader now that you've replaced the hard drive.

Reason for this is that the hard drive is assigned a unique device ID and even if you use Clonezilla on it, it may not copy exactly as you had hoped. What the bootloader was looking for is no longer there, and it doesn't recognize the other installation. You can use grub as a bootloader, which I can't recommend if you're using Secure Boot and TPM (this is pretty much default now). It will either work or screw up your ability to boot anything unless you make BIOS changes. So I'm not confident with that resolution. Also, it may not like BitLocker if you are using that either.

Instead, we will want to edit the Windows bootloader. Read here:

I'm assuming you are somewhat literate with this use scenario since you are posting diskpart from the command line. Proceed with caution and if you get annoyed enough there is a freeware bootloader editor at Visual BCD Editor - graphical bcdedit utility for Windows 7 to Windows 10 (not an endorsement).

Edit: Although I do not want to brick your system with this, in case the software is crap.. proceed with caution and consider the command-line option first. Basically the Microsoft method involves copying your existing boot record and creating two identical boot records, and then modifying them. It probably would be a matter of changing the drive to D on the 2nd entry but I could be wrong here.

See also: Dual-boot Repair Windows 10

Do not want you to destroy your boot record so you might want to back up before you do this, or at the least, make sure you have access to the recovery environment on backup.

Please let me know how this works for you.
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Hey Mike,
Thanks for your response. You make a lot of sense. I have been on this same trail and am some what familiar with the steps and options you have laid out. From what I have read I figured that I broke my bootloader, Or when I installed windows on the new drive it has a different GUID than the old drive, hence the BIOS cant find it to boot. I checked "Startup and Recovery" and "msconfig" and there is only one OS listed. I am going the CMD line route. I will let you know if I have any questions.


Windows Forum Team
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To the question regarding the missing boot, page file etc flags these will generally only show up on the actively booted drive, so I wouldn't worry about that.

As to the not showing both I would say it depends which screen you are referring to when you are able to select one disk or the other. UEFI firmware is actually smart enough to read the GPT partition table and locate bootable EFI systems. This "dual booting" screen would be firmware dependent and would indicate something with the GPT or EFI partition needs repair. The other "dual booting" screen would be a BCD store with a boot entry for each disk. This second screen would be the Windows Boot Manager being run from one drive. Both of these are viable methods of dual booting.

The other option (the one I'd recommend) would be to go to a single boot system and move your other copy of Windows into a VM. Hyper-V, Virtual box or VMware player are all free hyper visors available for that purpose.


The other option (the one I'd recommend) would be to go to a single boot system and move your other copy of Windows into a VM. Hyper-V, Virtual box or VMware player are all free hyper visors available for that purpose.
Thank you for your response Neemobeer. (Neat handle btw lol)
I am familiar with this option and work with VM's quite often. I dont want to burn up RAM. I dont like the effect VM's have on the host machine (performance wise). My goal here is to have Drive 1 for school, testing, and lab. Drive 2 for media/gaming. I would like to keep them both separate.