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Just successfully installed and ran Windows 8's Windows to Go on a USB external hard drive. However, after shutting down and removing the USB hard disk, whey I to start my laptop (with only Windows 7 installed), but it doesn't boot and trying to repair it doesn't work.

It seems that Windows 8 had corrupted the partition table on the laptop's hard drive, causing Windows 7 to fail to boot.

How do I fix that and avoid future problems of the same type?

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  • What happens if you plug the USB hard disk in again?
    – Mark Allen
    Sep 22, 2012 at 4:29
  • No problem in usb hard; win 8 boots normally when plugged again; the problem is laptop disk that doen't boot win 7 when removing the usb disk
    – user1687031
    Sep 22, 2012 at 8:14
  • this may relate superuser.com/questions/403250/…
    – user162160
    Sep 29, 2012 at 20:04

2 Answers 2

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To boot Windows Vista, 7, 8 from hard disk you need:

  1. Windows MBR on disk
  2. Windows NT6 PBR (partition boot record) on active partition
  3. \Boot\BCD (boot config data) on active partition with proper loader entries.
  4. \bootmgr on active partition

You can use Windows recovery/install DVD/USB, go to repair command prompt:

bootsect.exe - to write PBR and MBR

bootsect /nt60 all /mbr - should do

bcdboot.exe - to repair/create BCD (and bootmgr)

bcdboot c:\windows - should do (assuming Windows is installed on c:)

To set a partition as active you can use diskpart.exe (or DiskManagement within Windows).

Windows boot seqeuence from hard disk is always:

  1. BIOS loads and executes MBR from first hard disk
  2. MBR loads and executes PBR from active partition
  3. PBR loads and executes bootmgr from active partition
  4. bootmgr reads BCD and displays boot menu (or when only one loader entry in BCD bootmgr loads and executes winload.exe and so on ....)
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  • thanks for your help ; I opened command line from windows recovery to find that: - my windows partition which was assigned the letter 'C:' is healthy but having the last partition letter 'J:' - the 100MB boot partition (that was not appearing before) is taking the letter 'C:' and all the files you mentioned are existing ; so, before i try the fix command you mentioned 'bcdboot' , how to fix the unexpected change in partition letters ?
    – user1687031
    Sep 29, 2012 at 15:15
  • From Windows 7 DVD, I tried recovery, but got error : volume corrupted..; then tried bcdedit to set device partition from C: to J: but it didn't fix the problem ..; lastly I used diskpart to reassign partition J: letter to C: again and remove the system-reserved boot partition letter, but all that didn't work too !
    – user1687031
    Oct 1, 2012 at 8:12
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this is about multi boot with same issue http://www.multibooters.co.uk/articles/drive_letters.html and this solves a close problem with bcdedit too http://forum.acronis.com/forum/34337

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  • may be related too sevenforums.com/installation-setup/…
    – A.M.T
    Sep 29, 2012 at 21:58
  • Welcome to SuperUser! While those links may answer the question, it's preferred that you include the essential information in your answer. Link only answers are discouraged here as they're subject to link rot - if the external links become available, the answer is rendered useless.
    – Indrek
    Sep 30, 2012 at 0:37

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