NEED HELP: How to repair an UEFI bootable windows 10 disk

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  1. Posts : 16
    windows 10

    NEED HELP: How to repair an UEFI bootable windows 10 disk

    Scenario2 days ago I did a windows update that didn't require a reboot. I left the computer on over night while going to bed.When I tried to wake up my computer from sleep the day after it wouldn't start. It was going in some kind of loop without showing anything on the screen.I turned off the computer with the power button, which most likely caused the issue at hand, and tried to start the computer again. Now the computer is unable to load my windows 10 anymore.I had windows on 2 disks, one SSD and my i've also kept the windows on my old HDD for situations like this. Unfortunately my computer is not able to start the windows on any of these two disks anymore, so I had to start troubleshooting and try to fix them.NBThere's no bluescreen or anything like that. The computer stops loading with a black screen and the cursor blinking in the top right corner.TroubleshootingThe first thing I did was to make a USB windows 10 installation medium from another windows 10 comuter using microsofts own software for this. I tried to use this USB for startup repair on the SSD without any luck. I also tried opening CMD and run the following commands:

    • bootrec /fixmbr
    • bootrec /fixboot
    • bootrec /rebuildbdc

    These didn't fix anything so I alos tried running bootrec /scanos which found 1 windows installation and asked if I wanted to add it to boot menu. I answered with yes and it failed.With all these normal ways to fix a boot problem with windows failing I decided to install windows on my secondary SSD disk and work from that one to troubleshoot some more. This was installed booting the USB windows 10 installation medium in Legacy mode so the new SSD is using MBR compared to my two other disks being installed using GPT and UEFI.Troubleshooting with the new windowsWhen the new windows finally was installed, I opened disk management and a CMD window with adminstrator privileges.
    NEED HELP: How to repair an UEFI bootable windows 10 disk-disk-management.jpgThe red outline from the above picture shows my main windows on the old SSD. It's visible, but unable to allocate a drive letter to it so I can't browse it in file explorer.The green outline is my old HDD with windows installed. I can still browse this disk and all its files, but I can't boot with it for some reason.My next step was to check the disks using diskpart in the CMD window I opened. I ran the following commands.
    • list disk
    • list volume
    • sel vol 2
    • assign

    This succeeded to assign a drive letter to the disk. (see below picture)NEED HELP: How to repair an UEFI bootable windows 10 disk-diskpart-assigning-drive-letter.jpgI have outlined the two disks in question in red, but also outlined the volumes of the two disks as well. The red outline on the volumes is the SSD volumes. The green outline is for the old HDD volumes. As you can see, the main partition for the SSD has the hidden attriubute on it, while the main volume for the HDD doesn't. Which is why I can read the files on the HDD but not on the SSD.Else you can see that I was able to add a drive letter to the disk now, so I went back to file explorer to test opening it. Just ending up getting "access denied message". (See picture below)Then I opened "task manager -> create new task -> browse" and from this browsing window I'm now able to access the disk and see that all my files are still there. (Also see picture below)NEED HELP: How to repair an UEFI bootable windows 10 disk-m-not-accesible.jpgNEED HELP: How to repair an UEFI bootable windows 10 disk-task-manager-browse.jpgThe next thing I wanted to do is try and remove the HIDDEN attribute from the SSD volume/partition so that I can assign a drive letter the normal way and hopefully read the files from file explorer as usual. Do do this I opened up DISKPART again and ran the following commands:

    • list vol
    • sel vol 2
    • att vol clear hidden

    This gave me the following response Virtual Disk Service error: The object is not found. (see below picture)NEED HELP: How to repair an UEFI bootable windows 10 disk-diskpart-clear-hidden.jpgSo I did a comparison on the partitions on the SSD disk and the HDD disk to see why I can't clear the hidden attribute to browse the SSD normally.From what I can see, the SSD for some reason is lacking the primary partition and seem to have merged the primary partition together with the system partition. Which is most likely why I can't remove the HIDDEN attribute from this volume. The HDD on the other hand has its own system partition and its own primary partition. (see below picture, SSD in red and HDD in green)NEED HELP: How to repair an UEFI bootable windows 10 disk-diskpart-disk-comparison.jpgMy last resort so far was to try and update BIOS through my Legacy booted windows, but I was unable to do so, most likely because my BIOS is still set to UEFI boot and not Legacy, so it tried to boot any other devices on UEFI as default and doesn't go back into the Legacy windows unless I tell it to do so using boot options menu on F12.

    1. Preferably what I want is to make this SSD disk bootable again without losing any data. Is this possible
    2. If that is not possible, is it possible to make the disk readable either from an UEFI boot windows or a Legacy booted windows? This should be possible as I can read the disk just fine through Task Manager, right?

    • The current running windows is on Legacy/MBR
    • The two unbootable windows on SSD and HDD are using UEFI with GBT
    • The SSD partitions are hidden and unreadble in file explorer
    • The HDD partition is not hidden and can be read in file explorer
    • Too me it seems that either BIOS or something else are lacking some UEFI boot files which makes my two UEFI windows not boot. At least the HDD one should been bootable if the SSD got ruined because of a computer crash after updating hte windows on that particular disk.

    Does anyone have any good advices to get further with this issue?
      My Computer

  2. Posts : 42,983
    Win 10 Pro (22H2) (2nd PC is 22H2)

    Hi, rather than attempt to get a complete picture of what you're saying- which would take me a lot of time and some questions, I'm going to suggest this, assuming you haven't yet started the invaluable practice of using disk imaging routinely as we so often recommend. (e.g. Macrium Reflect (free) + its boot medium + external storage for image sets) - allows recovery without technical help from disk failure and ransomware to user error quite quickly.

    So here's my suggestion:
    Assuming you still have somewhere a valid system partition ('C:');

    1. Create a disk image of your C:
    2. Remove all other disks.
    3. Clean install Win 10 making sure the new system partition is large enough.
    4. Check it boots ok.
    5. Overwrite the newly created C: by restoring your image of your present system partition.
    6. Run Startup Repair.

    You should have a bootable system running your familiar Windows configuration.
    Last edited by dalchina; 05 Aug 2017 at 12:04.
      My Computers

  3. Posts : 16
    windows 10
    Thread Starter

    This by far not detailed enough. on how to fullfill these tasks that you're mentioning and I'm sitting left with so many questions.

    1: I have already done 1-4. The windows I've done a clean install from is booting on Lgacy, while the one I want to restore is on UEFI. How will that comply to the rest of your very small list of tasks.

    2: When you say "restore your image of your present system partition" I understand the present as in the clean install I just did. How will that make my old files available again?

    There's no way I can perform what you are thinking with the small list you gave me.
      My Computer

  4. Posts : 42,983
    Win 10 Pro (22H2) (2nd PC is 22H2)

    1. Do you know anything about disk imaging? If not, that's one big reason why you may not understand.
    1. Create a disk image of your C:
    - yet you say you have done that. Let me try to confirm that. Which disk imaging program did you use to create the image?
    3. May I ask what is preventing you from doing a UEFI clean install?

    Please note, I have, in the past, used exactly that procedure, and then found others here had also. It works.
      My Computers

  5. Posts : 16
    windows 10
    Thread Starter

    Sorry, I missread it last time. Didn't read it as making an image. I was a bit frustrated, so sorry for being rude in the other post.

    I have tried doing a UEFI clean install on my secondary SSD, but I just ended up with error messages. Even after converting the MBR to GDT. Which is why I installed a Legacy boot with MBR instead.

    Also, It's really important to me to not lose a lot of the files on the old SSD. Which is why I'm not just reinstalling windowson that disk just yet. I want to make it work and maybe learn something new on repairing a windows installation in the process so I can do it later if necessary.

    I'm not quite understanding exactly what you want me to do yet though.

    1: Create the disk image (I assume that is of the faulty disk that doesn't start)
    2: Remove all other disks
    3: Install fresh windows with large enough system partition. (is it important to do this with UEFI since the SSD that doesn't work is installed with UEFI? Or does that not matter because of step 5?)
    4: Check that it boots
    5: Overwrite the C (No idea how to do this)
    6: Run startup repair

    Then you have a point of restoring hte disk image again, which I don't understand why since you it's already done in 5?
      My Computer

  6. Posts : 42,983
    Win 10 Pro (22H2) (2nd PC is 22H2)

    Hi, the simplest reading of step 1 is to image just one partition - namely your Windows 'C:' partition that you want to use.

    (You could create a disk image of the whole disk, which then includes all the partitions- then later restore just C: - but I think for you if you just image the one partition that's simpler).
    I suggest you simply do that first.
    Get yourself a copy of Macrium Reflect (free) - it's got a huge help file and videos - there are even simple guides in tenforums for it.

    It has a boot disk which you can create if you need that so you can boot your non-working PC from that if you wish. (Other Tasks, Rescue Media in the screenshot below)

    Connect a USB disk to which you will write the image of C:

    NEED HELP: How to repair an UEFI bootable windows 10 disk-untitled.png

    You will see I've ticked only C: (Windows), and you can see what I'm going to click to start creating the image file.

    Note: I'm assuming you still have a usable Windows partition, GPT/UEFI compatible.

    Your original screenshots show a scattering of Windows partitions on various disks- by clean installing Windows to a disk without any others connected, then following the procedure I've outlined, you will have all relevant partitions on a single disk.

    In my first post I left a stray line below You should have a bootable system running your familiar Windows configuration.which I've now removed - my mistake when editing. Sorry. Removed line.
      My Computers

  7. Posts : 16
    windows 10
    Thread Starter

    I kinda still feel to new on using images to follow your "simple" how to list. I just don't want to do anything wrong which ends up deleting all my data without being able to recover it.

    Can you recommend a program that lets you make an image of a single partition like you recommend that I do.
    I know windows 10 has one, but that only creates on for the system I'm currently running, which isn't the one I want to make it from.
      My Computer

  8.   My Computers

  9. Posts : 16
    windows 10
    Thread Starter

    Thank you so much, I'll have a deeper look into this.
      My Computer

  10. Posts : 16
    windows 10
    Thread Starter

    So what I've done so far.

    1: create the image file of the non working partition

    2: installed a clean windows 10 using GPT/UEFI on my secondary SSD with all other disks removed.

    3: Made sure it worked and installed macrium reflect as a boot options.

    4: booted into macrium reflect and restored the non working C drive onto the newly created clean install to replace its C drive.

    5: ran startup repair, but without being able to repair. At least now I receive a log file.

    Tried running following commands from cmd again:
    Bootrec /scanos
    Bootrec /fixmbr
    Bootrec /fixboot
    Bootrec /rebuildbdc

    Still without luck. Any more suggestions from here?
      My Computer


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