When upgrading Windows Vista to Windows 7, some systems may encounter failure to upgrade error which causing computer to go into continual and endless reboot or restart cycles. Considering many Windows XP users may use Windows Vista as stepping stone to in-place upgrade XP to Windows 7, the Windows 7 upgrade failure and perpetual reboot cycle consequence may cause many inconvenience.

The symptom of the problem is that when attempting to upgrade from Windows Vista to Windows 7, the upgrade attempt may fail with the following message

This version of Windows could not be installed, Your previous version of Windows has been restored, and you can continue to use it.

However, after system reboot, the next start up or boot up of the machine will launch the upgrade process again only to fail with the same message as above, rendering system unusable with endless reboot cycle.

The exact cause the causing the Windows 7 upgrade failure is unknown, however the reason for continual endless reboot is caused by the fact that the computer’s Boot Configuration Database (BCD) store is modified in the Windows 7 upgrade process to make Windows 7 the default operating system. However, when the Windows 7 setup installation process failed, halted and reverted with restoration of Windows Vista operating system, BCD store has not edited to restore Windows Vista as the default booting operating system. Thus, the computer will continue to boot to the Windows 7 Setup and then fail with the same error message.

The resolution to the endless reboot issue after failure to upgrade to Windows 7 is easy – restore BCD database to its previous state, and Microsoft has provided detailed step-by-step guide in KB974078.

How to Fix Endless Continual Reboot Issue After Windows 7 Upgrade Failure

  1. Power on the computer or restart the computer.
  2. On initial start up, a boot entry menu should be shown (if it’s not, press F8 on system boots up). Select Windows Vista instead of Windows 7 Setup (which is the default at current failed state).
  3. Insert the Windows Vista media (download Windows Vista with SP2 ISO) if you don’t have one) into the drive and exit the Windows Vista Setup when its launched.
  4. Click Start -> All Programs -> Accessories, and then right-click the Command Prompt icon, and then click Run as Administrator to open elevated command prompt with administrator rights.
  5. Type the following command at a command prompt and press Enter:

    X:\boot\Bootsect.exe /NT60 All

    Replace X with the actual DVD physical or virtual drive letter where the Windows Vista installation media is located.

  6. Restart your computer.

The issue can affect all editions of Windows Vista RTM, SP1 and SP2.