Windows 10: Windows 10 booting problem - volume letters changed, system and boot volumes not assigned

Discus and support Windows 10 booting problem - volume letters changed, system and boot volumes not assigned in Windows 10 Installation and Upgrade to solve the problem; Hello Microsoft Community, Yesterday 4/5/2021 I encountered a problem when booting Windows 10 on my PC. I saw the initial BIOS screen and after a few... Discussion in 'Windows 10 Installation and Upgrade' started by Mr_Arkady, Apr 6, 2021.

  1. Mr_Arkady Win User

    Windows 10 booting problem - volume letters changed, system and boot volumes not assigned


    Hello Microsoft Community,


    Yesterday 4/5/2021 I encountered a problem when booting Windows 10 on my PC. I saw the initial BIOS screen and after a few seconds a black screen occured. I was so surprised because on the same day morning everything was working fine and the system shut down without any problems.


    I entered the emergency screen to run the repair toolkit but it failed with the following error:

    Windows 10 booting problem - volume letters changed, system and boot volumes not assigned c6382d64-5d1f-4394-887d-319b84750a5b?upload=true.png

    It was so weird because my Windows installation is on drive C.

    I did not install any software or drivers/BIOS updates, the only thing I remember was the warning from security center that Windows Defender is outdated so I clicked to update it operation completed successfully.
    Next, I decided to restore my instance to the last correct version 3/31/2021 but that did not solve the problem.


    Then, I navigated to the command window to check the setup of disks and volumes.

    I have two disks: 0 - HDD and 1 - SSD, both GPT and the disk 1 is a bootable UEFI device with WIndows 10.

    Windows 10 booting problem - volume letters changed, system and boot volumes not assigned 3d04514b-ce05-40d6-aac1-9f1cb4599359?upload=true.png


    Then, I looked through the volumes and saw the configuration has changed:

    Windows 10 booting problem - volume letters changed, system and boot volumes not assigned 2f3c1c4e-4b08-4aee-9af7-76f02b81baca?upload=true.png


    Volume 0 is my HDD disk with one partition that was originally letter D.

    Volume 1 is my SSD disk primary partition with the Windows installation that was originally letter C.

    Volume 2 was the recovery volume.

    Volume 3 was the boot volume there was no volume letter, but I assigned V to be able to navigate to this volume.

    When I listed all paritions for SSD disk I saw the same list of partitions but with information which one is primary, system and recovery.


    I tried to fix the problem by rebuilding the MBR using /FixMbr /FixBoot /ScanOs /RebuildBcd - it failed on missing privileges for FixBoot, ScanOs did not return any rows.

    Then, I manually corrected volume letters and rebuilt the MBR once again - it failed same as above.

    Finally, I tried to manually setup the primary partition as bootable but it failed with information that the partition needs to be MBR not GPT UEFI to use the active command.


    I navigated through system and data partitions and I saw all files were available.

    I found the log that was generated during the repair process - I saw a number of tests executed and all of them were passed.


    Now, I am completely lost and I have no idea how to fix the problem. I hope, there is a chance to fix the configuration, otherwise I will need to install Windows 10 from scratch.

    I would be very grateful for your help in solving the problem.

    Please, let me know if you have encountered a similar problem, if you know how to fix the configuration or if you have any recommendations on how to avoid such issues in the future.


    Thank you,

    Mr Arkady

    :)
     
    Mr_Arkady, Apr 6, 2021
    #1
  2. nanohead Win User

    Changing the system volume drive letter safe?

    It depends. Need some more information. Is your boot volume c: ? If so, then others can be changed around as needed, but there may be collateral damage. Usually, if there are pointers set in the registry, as long as you use the storage management plugin to change the drive letter assignments, most things should work.

    Trouble comes in the form of applications that keep file system information (folders, path names, etc) in files that are stored in directories during installation. Those usually cannot be changed easily, unless you know that they are there and where they are....

    What drive letters are you trying to change specifically, and what is the operating system
     
    nanohead, Apr 6, 2021
    #2
  3. Mark7805 Win User
    Changing the system volume drive letter safe?

    The operating system WAS on c:\ (before I changed windows over to my SATA), NOW it is on E:\. Keep in mind I have 3 hard drives at the moment.
     
    Mark7805, Apr 6, 2021
    #3
  4. Mark7805 Win User

    Windows 10 booting problem - volume letters changed, system and boot volumes not assigned

    Changing the system volume drive letter safe?

    Ever since I reformated, my drive letters have changed besides C:\ and I would like to change back the other 2 drive letters.(One being the system volume letter) just so the programs I use to have still work. Is this safe? What are some negatives?
     
    Mark7805, Apr 6, 2021
    #4
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Windows 10 booting problem - volume letters changed, system and boot volumes not assigned

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