Windows won't boot after changing MBR signature


  1. Posts : 1
    Windows 7 Ultimate x 64
       #1

    Windows won't boot after changing MBR signature


    Greetings all,
    This is my first post so bare with me if I've done something wrong. I was using the the mbrfix tool today to change a disk signature per a knowledge based article. Basically I ran the following command:

    > mbrfix /drive c readsignature
    >4BEE4158 (this was the output)
    >mbrfix drive c writevalue 3

    After this I rebooted and now the computer will not recognize the hard disk(s) at all. I have tried using the windows installation media to repair the disk to no avail. Even the DISKPART command "list disk" shows no disks. I played with something I have little knowledge of and now I'm stuck. Is there anything I can do ???

    Thanks in advance.
    -Mike
      My Computer


  2. Posts : 21,004
    Desk1 7 Home Prem / Desk2 10 Pro / Main lap Asus ROG 10 Pro 2 laptop Toshiba 7 Pro Asus P2520 7 & 10
       #2

    Hello and welcome Mike mate first mistake in my mind is using one of those aftermarket softwares to fix something like that - something that I will never do.

    Second mate it is very hard to advise when we do not know what we are dealing with so please can you update your profile with the system specs
    System Info - See Your System Specs

    Now have you tried a safe boot at all? If you can get into that you might have more luck with the DISKPART function. Moreover are the drives showing in the BIOS??
      My Computer


  3. mjf
    Posts : 5,969
    Windows 7x64 Home Premium SP1
       #3

    awadbigmo said:
    I was using the the mbrfix tool today to change a disk signature per a knowledge based article. Basically I ran the following command:

    > mbrfix /drive c readsignature
    >4BEE4158 (this was the output)
    >mbrfix drive c writevalue 3

    After this I rebooted and now the computer will not recognize the hard disk(s) at all. I have tried using the windows installation media to repair the disk to no avail. Even the DISKPART command "list disk" shows no disks. I played with something I have little knowledge of and now I'm stuck. Is there anything I can do ???

    Thanks in advance.
    -Mike
    I'm not sure what you were attempting to achieve. So some more information could be useful. When you change disk signatures, particularly with the boot disk, you need to know what and why you are doing it.

    To fix an MBR boot problem you could disconnect all your drives apart from the boot drive then follow this procedure:
    https://support.microsoft.com/en-us/kb/927392
      My Computer


  4. mjf
    Posts : 5,969
    Windows 7x64 Home Premium SP1
       #4

    uchuk said:
    Disk signature is stored in three places:
    1) MBR
    2) BCD registry hive on System Reserved Partition (or EFI System Partition)
    3) HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices registry key in C:\Windows\System32\Config\SYSTEM registry hive
    This is the case on the boot drive. Other local/data drives don't have a BCD etc. So if for some unknown reason you change the disk signature on the boot drive your PC probably won't even boot - is this the case?
    If so the bootrec procedures should fix the problem.

    I've had disk signature changes on non boot drives (external) and haven't had a problem.

    This link may also help
    View and Change the Disk Signature in the MBR - Multibooters.com
      My Computer


  5. Posts : 3,786
    win 8 32 bit
       #5

    When you do anything like this is to be able to role back if it goes wrong did you note the original signature so you can put that back?
      My Computer


 

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