Feb 28, 2012

SOLVED: Win 7 SP1 Install Error 0x800f0a12 on Dual-Boot System

I have a system that boots Ubuntu10.04 from sda and Windows 7 from sdb. Sdb is a recent reinstall of Win 7 on an SSD.

Windows Update finally notified me that  it had downloaded SP1 for installation, and my troubles began. Kept getting Error 0x800f0a12, which isn't terribly descriptive.
I tried a number of suggestions I found on the web, including marking the System Reserved partition active (turns out it was in the first place), giving it a drive letter, and other "solutions".
Then I found this page on the Microsoft site:  http://windows.microsoft.com/en-US/windows7/windows-7-windows-server-2008-r2-service-pack-1-sp1-installation-error-0x800F0A12
The first suggestion in the web page fitting my error code was to make sure the system volume was mounted using:
mountvol /E
Nope, same error.
Read a little more in the page and saw this:

If a disk management tool from another software manufacturer was used to copy (sometimes called clone) disks or partitions on your computer, the SP1 installer might not be able to identify the correct system files.
  1. Turn off your computer and physically disconnect any external disks or drives that aren’t required for startingWindows. 
That worked! Windows must not have liked having the GRUB2 startup manager on the first disk. Or something..

Anyway, it got me past the problem.