1. Joined : Jan 2014
    Posts : 728
    Win 10
       14 Dec 2014 #1

    Windows 10 update corrupted dual boot options

    When I first installed the Win 10 Preview, it set up a dual boot (actually triple boot, 3 OS's - Win 7, Win 8.1 and Win 10). One of the Win 10 updates corrupted it. I've tried to fix it by booting with all 3 OS install discs and running "bootrec.exe".

    Bootrec.exe /rebuildbcd returns "Total identified windows installations 0"
    Bootrec.exe/scanos lists all 3 OS'

    Originally, I had a dual boot with Win 7/Win 8.1 until I installed the Win 10 Preview.

    I no longer get boot options. On a power on or restart it will either boot directly to Win 10 Preview or to Win 7. I have to enter the BIOS and select which OS I want.

      My System SpecsSystem Spec

  2.    14 Dec 2014 #2

    I had the same thing once.
    Try holding Shift then press Restart, on the blue screen choose 'Change Defaults', the 'Timeout' entry might be 0
    Change it back to 30 seconds or whatever.
      My System SpecsSystem Spec

  3. Joined : Jan 2014
    Posts : 728
    Win 10
       14 Dec 2014 #3

    "Shift then Restart" when or where?

    I can check the timeout setting in msconfig.
      My System SpecsSystem Spec

  4.    14 Dec 2014 #4

    Bring up Power Menu, hold Shift before pressing Restart.
    For some reason it doesn't matter what's listed in msconfig.
    (might not be the problem but it's worth a shot)
      My System SpecsSystem Spec

  5. Joined : Jan 2014
    Posts : 728
    Win 10
       14 Dec 2014 #5

    Thanks for the timeout fix. It was set to 0 in the primary system's "msconfig" for the OS boot selection. Setting it back to 30 seconds fixed the problem.

      My System SpecsSystem Spec

  6.    14 Dec 2014 #6

      My System SpecsSystem Spec

  7. Joined : Nov 2013
    Posts : 1,397
    Win-7Prox64 Win-8.1Prox64 Win-10Prox64
       14 Dec 2014 #7

    Yep get used to that one major updates 10 will always do that :/
      My System SpecsSystem Spec

  8. Joined : Jun 2014
    Posts : 4,498
    Windows 10 Pro
       14 Dec 2014 #8

    I dual boot and so far it hasn't happened to me. Good info to have in case it ever does happen though.
      My System SpecsSystem Spec


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