Microsoft distributes a stability and reliability update for Windows 7 and Windows Server 2008 R2, KB974431, which intends to improve the stability and reliability of Windows 7 and of Windows Server 2008 R2 in various scenarios, such as missing characters in Microsoft Office-created PDF file, blank screen is displayed on computer with secondary monitor or does not have Physical Address Extension (PAE) enabled when resuming from hibernation, Windows Media Player playback issue and end entity certificate installation failure in IE.

However, when Windows Update installing KB974431 update, the following error message may be displayed when Windows is configuring the updates after system reboot, and the installation of the update fails, with error code of C004F050.

The error happens because the Windows operating system cannot pass genuine Windows validation (WGA). KB974431 incorporates a built-in mechanism which check for genuineness and authenticity of Windows 7 or Windows Server 2008 R2 OS installed on the PC, before it allows itself to be installed. If the validation fails, or return invalid or not genuine status, installation of KB974431 will fail.

Here’s how to fix KB974431 installation failure due to 0xC004F050 error:

  1. Run command prompt window as administrator.
  2. Run the following command to reset all system files to default and clean the system from hack or crack:

    sfc /scannow

  3. If activation grace period has expired (e.g. black background desktop), run the following command to rearm Windows to extend activation grace period for another 30 days (i.e. genuine for another 30 days):

    slmgr /rearm

  4. Restart the computer.
  5. Run Windows Update to install KB974431 update again.
  6. If Windows loses activated status, perform activation again.

If the above resolution does not work, try to uninstall any previous Windows 7 activation crack or loader or hack to bypass Windows 7 activation that has been installed previously manually. Worst scenario, user will probably need to in-place upgrade Windows 7 again by select Upgrade installation to have a new, clean, legit Windows 7 installed with all applications and data migrated automatically.