Windows 8 and 8.1 Forums


Windows 7/8 Dual Boot Drive Letter Issue

  1. #1


    Krakow
    Posts : 7
    windows 7/8 dual boot

    Windows 7/8 Dual Boot Drive Letter Issue


    Hi guys,

    I've got a problem with my dual boot setup:

    I've installed win8, selected an empty partition, booted it, everything peachy.

    The only surprising thing was that driver letters where switched: my windows 7 install and data was now in D: drive and windows 8 install appropiated C: letter drive without consulting me.

    This became a problem came when I tried to boot windows 7 and an annoying startup repair assistant showed up.

    Tried autorepair but no luck. [to be honest, I let it unattended and don't know what happened, don't even know if it finished since the battery died, but it lasts at least 2 hours, and that should be enough, right?]

    Then read somewhere changing active partition to win7 could help. Bad idea: now no boot at all.

    After a failed attempt to autorepair with windows 8 dvd restore utility I managed to restore windows 8 dual boot menu with win8 install dvd -> repair console -> bootrec /fixboot bootrec /fixmbr and bootrec /rebuildbcd commands, but windows 7 is still not loading: it says it can't find winload.exe or it is corrupt, and I guess it has something to do with the fact that it is now in D: drive

    This is my current bcdedit output in windows 8:

    Windows Boot Manager
    --------------------
    identifier {bootmgr}
    device partition=C:
    description Windows Boot Manager
    locale en-us
    inherit {globalsettings}
    default {current}
    resumeobject {186227ae-b91b-11e1-9b6c-1c7508fb9bfe}
    displayorder {current}
    {e1b5dcd9-b960-11e1-b749-d6509e56593f}
    toolsdisplayorder {memdiag}
    timeout 30

    Windows Boot Loader
    -------------------
    identifier {current}
    device partition=C:
    path \windows\system32\winload.exe
    description Windows 8
    locale en-us
    inherit {bootloadersettings}
    allowedinmemorysettings 0x15000075
    osdevice partition=C:
    systemroot \windows
    resumeobject {186227ae-b91b-11e1-9b6c-1c7508fb9bfe}
    nx OptIn
    bootmenupolicy Standard
    detecthal Yes

    Windows Boot Loader
    -------------------
    identifier {e1b5dcd9-b960-11e1-b749-d6509e56593f}
    device partition=D:
    path \Windows\system32\winload.exe
    description Windows 7 Ultimate
    locale es-ES
    osdevice partition=D:
    systemroot \Windows
    bootmenupolicy Standard

    Funny thing is preinstalled PB laptop has a system 100MB partition currently containing a bunch of win7 boot files. Isn't the loader path and drive supposed to be somewhere there?
    Any suggestions?
    Last edited by gaelow; 18 Jun 2012 at 03:56.

      My System SpecsSystem Spec

  2. #2


    INDIA
    Posts : 148
    Windows 8 RP, Windows 7


    Quote Originally Posted by gaelow View Post
    Hi guys,

    I've got a problem with my dual boot setup:

    I've installed win8, selected an empty partition, booted it, everything peachy.

    The only surprising thing was that driver letters where switched: my windows 7 install and data was now in D: drive and windows 8 install appropiated C: letter drive without consulting me.

    This became a problem came when I tried to boot windows 7 and an annoying startup repair assistant showed up.

    Tried autorepair but no luck. [to be honest, I let it unattended and don't know what happened, don't even know if it finished since the battery died, but it lasts at least 2 hours, and that should be enough, right?]

    Then read somewhere changing active partition to win7 could help. Bad idea: now no boot at all.

    After a failed attempt to autorepair with windows 8 dvd restore utility I managed to restore windows 8 dual boot menu with win8 install dvd -> repair console -> bootrec /fixboot bootrec /fixmbr and bootrec /rebuildbcd commands, but windows 7 is still not loading: it says it can't find winload.exe or it is corrupt, and I guess it has something to do with the fact that it is now in D: drive

    This is my current bcdedit output in windows 8:

    Windows Boot Manager
    --------------------
    identifier {bootmgr}
    device partition=C:
    description Windows Boot Manager
    locale en-us
    inherit {globalsettings}
    default {current}
    resumeobject {186227ae-b91b-11e1-9b6c-1c7508fb9bfe}
    displayorder {current}
    {e1b5dcd9-b960-11e1-b749-d6509e56593f}
    toolsdisplayorder {memdiag}
    timeout 30

    Windows Boot Loader
    -------------------
    identifier {current}
    device partition=C:
    path \windows\system32\winload.exe
    description Windows 8
    locale en-us
    inherit {bootloadersettings}
    allowedinmemorysettings 0x15000075
    osdevice partition=C:
    systemroot \windows
    resumeobject {186227ae-b91b-11e1-9b6c-1c7508fb9bfe}
    nx OptIn
    bootmenupolicy Standard
    detecthal Yes

    Windows Boot Loader
    -------------------
    identifier {e1b5dcd9-b960-11e1-b749-d6509e56593f}
    device partition=D:
    path \Windows\system32\winload.exe
    description Windows 7 Ultimate
    locale es-ES
    osdevice partition=D:
    systemroot \Windows
    bootmenupolicy Standard

    Funny thing is preinstalled PB laptop has a system 100MB partition currently containing a bunch of win7 boot files. Isn't the loader path and drive supposed to be somewhere there?
    Any suggestions?
    Try to add Windows 7 boot entry using EasyBCD and see that if it works
      My System SpecsSystem Spec

  3. #3


    Krakow
    Posts : 7
    windows 7/8 dual boot


    No luck, keeps saying something about winload.exe signature cannot be verified. Worst than that. I realized I have two BCD: one in my "new" c: drive for win8 with win7 and win8 entries and another in my d: drive (previously c with win7 entry. I guess the one active is windows 8, but since windows 7 unit also has one, I'm a little bit confused.

    Since I have my windows 7 install files built in the laptop's recovery partition instead of a dvd, I downloaded and burned a windows 7 sp1 install disc, but it doesn't allow me to enter repair mode when I pick windows 7, it says cannot enter repair mode for this os or something like that, I guess it's related to this sign problem or whatever.

    Any other suggestions?
      My System SpecsSystem Spec

  4. #4


    INDIA
    Posts : 148
    Windows 8 RP, Windows 7


    Quote Originally Posted by gaelow View Post
    No luck, keeps saying something about winload.exe signature cannot be verified....

    This link might help you

    Driver Signature Enforcement error screen can't be cleared, even after signing

      My System SpecsSystem Spec

  5. #5


    Portsmouth Hants
    Posts : 772
    Windows 8.1 Pro with Media Center


    If you multiboot, most Windows systems report being on the "C:" drive.

    It's a difficult thing to get one's head around, but the "C:" designation is just an alias - another name, or shortcut for the boot volume. Windows 8 now consistently uses it for the current drive with the Windows folder on it.

    It was not always so - Not only could XP be installed on any assigned drive letter, you could have more than one XP installation in the same partition - as long as the Windows folder had a different name - so you could multiboot to Windows XP on C:\Windows, Windows XP on C:\Windows.001, Windows XP on D:\Windows, etc.,

    It is outdated, limiting and confusing to just use the letters A..Z as drive designators, or even the volume numbers - it should be either logical as in Linux (hd0,0), (hd0,1), (hd1,0), etc, or using the unique volume label (up to 32 characters for NTFS, 11 for FAT), which could be automatically assigned by Windows OSs -A..99999999999999999999999999999999 for example. The "C:" alias could still be used by the OS internally for consistency.

    The moral is: clearly label each drive volume and make sure that the BCD entry has the volume name included
      My System SpecsSystem Spec

  6. #6


    Krakow
    Posts : 7
    windows 7/8 dual boot


    Ok,

    First of all I solved the signature issue disabling x64 driver signature checking (I guess this was necessary due to some device encription drives (freeotfe) I had installed on win7, which required to disable the driver checking which was somehow reenabled when I tried to restore windows 7)

    Anyway, now I'm (almost) back at my original point. It means: I can enter the repair mode and console on windows 7 install, which means the loader is close to working, but when I execute startup repair it found no errors, and yet I cannot start windows, because it automatically falls back to this repair mode every time I select to boot windows 7.

    Second: Each partition has a disctinct label but I don't know how to specify other than the drive letter using bcdedit command. Is there a bcdedit /set {id} osdevice label="mywin7partitionlabel" command or something?

    Any more ideas?
      My System SpecsSystem Spec

  7. #7


    INDIA
    Posts : 148
    Windows 8 RP, Windows 7


    Quote Originally Posted by gaelow View Post
    ....Second: Each partition has a disctinct label but I don't know how to specify other than the drive letter using bcdedit command. Is there a bcdedit /set {id} osdevice label="mywin7partitionlabel" command or something?....
    Glad to hear that you got rid of signature issue

    Second way is:

    bcdedit /set { YOUR GUID NUMBER } osdevice partition={drive of Windows 7}:
    for ex. bcdedit /set {e1b5dcd9-b960-11e1-b749-d6509e56593f} osdevice partition=D:
      My System SpecsSystem Spec

  8. #8


    Portsmouth Hants
    Posts : 772
    Windows 8.1 Pro with Media Center


    I suppose I'd delete the windows 8 partition and repair the Windows 7 installation from the windows 7 install DVD first installing another copy of windows 7 where the windows 8 was as a fallback system. I would not bother about activating it.

    I'd then try to repair the original windows 7 installation, first by using the DVD startup repair tools then the repair install method, and if they do not work, using the command line, still from the DVD.

    If this seems reasonable to you I'll walk you through it
      My System SpecsSystem Spec

  9. #9


    Krakow
    Posts : 7
    windows 7/8 dual boot


    Ok, I finally solved it, here is how:

    a) Forget about dual letter issues. There are none at all, when using bcdedit just work with the current letter assignment whatever it is (I guess internally the volume id is what's stored, so when you run bcdedit /enum it will always list the whatever-OS-install-currently-running's drive as C: )

    b) Before dual installing windows 8, I had a previous bcd fix on my windows 7 install in order to load an unsigned driver which windows 8 install reverted: That's what was causing the "cannot verify winload.exe digital signature" problem.

    After learning this, here's what I did:

    1) I booted windows 8 and erased ALL the entries on my BCD file one by one using bcdedit /delete {entryguid} (including {bootmbr} and some not showing in the os selection menu), from a cmd console with admin rights.

    2) I restored the erased entries booting with a windows 7 installation disk (after language selection click next and then select repair system: the lack of entries on the BCD file is automatically detected and solved)

    3) The key thing: I had to put windows 7 bcd entry into test signing mode and disabling integrity checks, just as it was before windows 8 install messed it up, so I booted again windows 8 and input the following commands (on a cmd console with admin rights):

    3.1) bcdedit /set {win7entryguid} loadoptions DDISABLE_INTEGRITY_CHECKS
    3.2) bcdedit /set {win7entryguid} TESTSIGNING ON
    3.3) bcdedit /set {win7entryguid} NOINTEGRITYCHECKS ON

    For some reason it didn't work until I did 3.3, despite some forums state that 3.1 and 3.2 is enough.

    That's all, hope it can eventually help somebody else.

    Regards and all my gratitude to fafhrd and kapilarya. Thanks for your help!
    Last edited by gaelow; 20 Jun 2012 at 17:41.
      My System SpecsSystem Spec

  10. #10


    Posts : 5,360
    7/8/ubuntu/Linux Deepin


    You could have done it like this:

    bcdedit /create /d "Whatever Name" /application osloader

    I don't think you can use the label like that - you would need the guid
      My System SpecsSystem Spec

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