Windows 10: Fixing an inadvertent dual boot of Windows 10

Discus and support Fixing an inadvertent dual boot of Windows 10 in Windows 10 Installation and Upgrade to solve the problem; My original boot drive for this computer was failing. Apparently a memory chip had also gone bad, which certainly complicated things further. (I... Discussion in 'Windows 10 Installation and Upgrade' started by KHaining, Dec 14, 2015.

  1. KHaining Win User

    Fixing an inadvertent dual boot of Windows 10

    My original boot drive for this computer was failing. Apparently a memory chip had also gone bad, which certainly complicated things further. (I suffered through a day with one blue screen of death after another -- my computer could not stay booted for longer than 30 seconds before it would crash with a number of different error messages. Once I could get into safe mode, it was stable for a bit longer.) At any rate, I made a USB install disk for Windows 10 on another machine, but the only way I could get my computer to boot from the USB was to get to Windows first and THEN go into recovery mode and tell it to boot from the USB drive. Once I did that, I installed a fresh version of Windows 10 onto a new, much larger drive.

    Eventually I want to get rid of the old drive, since it's been unreliable (damaged sectors and files, can't be repaired through chkdsk, etc.). In fact, I'm ready to reformat it now. But I'm afraid that my computer is still using the old drive for booting and that Windows 10 -- when it was installed onto the new drive -- didn't install the necessary boot partition for my new drive to boot as a solo operation.

    I think this because my computer will not boot unless I force it to go to the BIOS first and then exit. If I don't go to the BIOS, it just sort of hangs there with no activity and never makes it as far as a Windows logon screen (or even a choice of boot options). If I press F10 to force it to bring up the BIOS set-up menu, once that loads I just need to exit without making any changes and then the computer will boot into the new Win10 partition on the new drive.

    When I look at disk management, it shows me one large partition for my new drive which is defined as "Healthy (Boot, Page File, Crash Dump, Primary Partition)". The old failing drive is subdivided into 6 partitions, 3 of which are labeled Recovery, one is Primary, and the other is the EFI System Partition. I'm thinking the EFI System Partition is what needed to be on my new drive.

    How do I fix this? Or do I need to fix this?

    This has been a saga of one headache after another... the failed boot drive, the failed memory, having to refresh Windows again on the newer hard drive (because apparently the memory fault corrupted both my Windows 10 new installation as well as totally trashed an external hard drive which was previously fine). So I want to make sure I don't cause any further headaches for myself by doing the wrong thing. If I can use the Windows Disk Management tool to fix things, I'll need step-by-step instructions since I've never partitioned (or re-partitioned) a hard drive before.

    Thank you in advance for any help you can give me.

    KHaining, Dec 14, 2015

  2. Install Win 10 Pro as dual boot currently have Win 7 Pro

    I recommend partitioning before from within Windows 7's disk management, especially to avoid inadvertent mistakes.

    Partitioning in advance also reduces the amount of setup chores you have to do. All you need to do is boot from the install media, then choose the partition. Learn more:

    How to: setup a dual boot configuration with Windows
    10 and previous versions of Windows
    Andre Da Costa, Dec 14, 2015
  3. July_2017update kills laptop and desktop performance.

    Well, the creator's update came out. Had the screensaver problem with photo gallery, fixed it. But I have a dual boot machine with Win10 home and Debian 8 as my media server, and the update wiped the dual boot out. So if you have a dual boot machine,
    be prepared.
    Joe Tannenbaum, Dec 14, 2015
  4. NavyLCDR New Member

    Fixing an inadvertent dual boot of Windows 10

    I would install MiniTool Partition Wizard Free. Use that to shrink your Windows 10 partition on the new hard drive and create an empty space equal to the partition size of the EFI system partition on the old hard drive. Copy the EFI system partition from the old hard drive to the newly created empty space on the new hard drive. Make sure it gets marked as active on the new hard drive. After partition wizard finishes everything then just disconnect the cable from the old hard drive and see if your computer will boot to the new hard drive installed alone.

    An alternative method would be to install EasyBCD. There is a function in EasyBCD to move the boot files to a different hard drive/partition. You might be able to just point the new BCD location to the Windows partition on the new hard drive. Then disconnect the cable from the old hard drive and see what happens. I don't like having my boot files on my Windows partition myself, but that is just my personal preference.

    Best Free Partition Manager for Windows | MiniTool Partition Free

    EasyBCD - NeoSmart Technologies
    NavyLCDR, Dec 14, 2015
  5. WHS
    whs Win User
  6. KHaining Win User
    Thank you, NavyLCDR, and thank you, whs, for both your suggestions to my dilemma. I've been offline for several days while my computer got sorted out and I've finally got a bare minimum Windows 10 installation completed. But at last it's working, and -- glory be! -- it's actually booting from my new hard drive now.

    I tried to use the EasyBCD first, but got an error message and was unable to do anything with it. I can't recall now what the exact message was -- something about the drive being locked, maybe? -- but even though it didn't help in this particular situation it seems like a good tool to know about for future reference.

    I did use the Mini Tool Partition Wizard Free to split my drive, but in the end I just didn't trust my failing hard drive to have reliable partitions to copy from so I opted to do yet another clean install of Windows 10. This time round I was greatly aided by the TenForums tutorial, in which the #13 section for those with UEFI systems was particularly helpful.

    I'm a little amazed at Windows 10's express installation that helped get me in this mess in the first place. It seems to me that an express set-up on a new drive ought to assume both that (1) the user doing the installation is likely more of a novice; and (2) if you're going to put Windows 10 on a completely new drive, the chances are extremely high that you'll want to boot off this new drive. Perhaps no one has looked too closely at the installation routines since the technical preview edition of Windows (when it was a lot more likely that people actually did want dual boot systems).

    At any rate, at last I seem to have a functioning system again. Now it's just the long road to rebuilding my computer -- reinstalling all my software and re-customizing all my programs... (sigh)

    Thanks again for your help! And best wishes for the holidays and the coming New Year.

    KHaining, Apr 4, 2018

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