Roughly two weeks ago Microsoft released Windows 7 Service Pack 1 to the general public. As is standard practice for most IT departments I held off on rolling out Windows 7 SP1 until any issues with the update had been identified. Since no issues have been identified that would affect the systems I manage I began rolling out the update this week. Unlike many of Microsoft’s previous operating system service packs, Windows 7 SP1 serves primarily as a roll-up of previous security updates. Still, there are a few updates included in SP1 that people will want to take advantage of — many of which are performance related. For whatever reason the update to SP1 hasn’t been as smooth as previous service packs. From what I’ve read on the interweb the installation of SP1 has become downright frustrating for many.
In many cases the update attempt simply ends with a vague error, Update error 800F0A12. I encountered this error on several computers I attempted to update. When I first experienced an installation issue I followed the normal troubleshooting steps. Disable anti-virus. Ok, I know, why didn’t I disable it to begin with? Well the simple truth is that most anti-virus solutions no longer interfere with software installations or OS updates. Unfortunately disabling anti-virus had no effect on resolving the error. Next step — Check for free space on the boot partition. Check — I had plenty of free space. Lastly, check for software that may be locking the disk and preventing the update from completing successfully. Nope, no software was present that could interfere in that manner. So now I was out of ideas. That was until I stumbled upon this article. Windows 7 utilizes a small system partition. This partition was not being automatically mounted and as a result the update to SP1 was failing. All I had to do was open a command prompt, running it elevated as Administrator, and type “mountvol /E” at the command prompt. Then I rebooted and voila — SP1 installed without a hitch. This same solution solved the error on all the computers I encountered the 800F0A12 error on.
If you experience difficulty installing Windows 7 SP 1 follow these troubleshooting steps.
- Make sure you a minimum of 1GB free space on the boot drive.
- Try disabling anti-virus and running the update again.
- Confirm that disk backup/cloning software is disabled and the associated services have been stopped. To view what services are installed on your computer and to stop services type “services.msc” in the search field or run line of the start menu.
- Make sure the system partition is being automatically mounted. You can insure the partition is being mounted by running a command prompt elevated as Administrator and entering “mountvol /E” at the command prompt. Then reboot and try the update again.
For more information see this article: http://windows.microsoft.com/en-US/windows7/windows-7-windows-server-2008-r2-service-pack-1-sp1-installation-error-0x800F0A12
Mar 16th, 2011 at 2:28 pm
also ensure the system partition is active.
to activate do the following:
1. Start->Administrative Tools->Computer Management
if you don’t have “Administrative Tools” enabled, do
Start->Run… and type “compmgmt.msc /s” in the input box
If you don’t have “Run…” enabled, right-click on the toolbar, click on “Properties”,
click the “Start Menu” tab, click on “Customize…”, scroll down to where it says
“Run command”, click the box next to it and ensure the box is now checked. Then
click “OK”, and “OK” again.
2. On the left-hand side, open up “Disk Management” (under “Storage”) by clicking on it.
3. On the list in the center panel, right-click the list item that reads “SYSTEM”, and click
the “Mark Partition as Active” item. If it is greyed-out, the partition is already active,
so this won’t help with your problem.
4. Exit Computer Management and retry your SP1 install.
[Reply]
wel51x Reply:
March 16th, 2011 at 2:31 pm
this html implementation did not preserve my original indentations, so the legibility of the above is not great. hopefully you can get through it.
[Reply]
Paddy Reply:
February 6th, 2013 at 2:00 pm
Hey mate thanks a bunch this solved my problem :-)
[Reply]
Jul 21st, 2011 at 1:03 pm
I ran into another variation of this bug when trying to install SP1. I have two disks with multiple operating systems installed, so I boot from an IDE disk with my bootmanager installed, then run Windows 7 from a SATA disk off a single partition. It turns out that Windows 7 gets confused by the fact that the IDE disk is the main boot disk with its own active partition, so it apparently looks in the active partition on the IDE disk and errors out when it doesn’t find the boot config data it needs for SP1 there. I was able to get it working by disabling the IDE disk in the BIOS, I now notice that simply changing the boot disk order in the BIOS also appears to work.
I had a similar issue when I was installing Win7 to the SATA disk, where it would let me choose the partition but wouldn’t install to it. When I hit Shift+F10 to drop to a command prompt and check the Setup log files, there were repeated errors saying “The selected disk is not the computer’s boot disk.” I read online that the installer gets confused by other disks, so I worked around that also by unplugging the IDE disk, seems like a similar problem. Looks like Microsoft is really pushing the single OS install, considering it would be straightforward to put in logic to handle these other cases also.
[Reply]
Omri Reply:
June 26th, 2012 at 11:20 pm
@Sprewell-
Hear, hear! I had the same update problem as everyone on this thread, but most of the solutions were about making one *partition* on the physical drive active. I set up my dualboot on two separate hard drives, so there’s only one partition on my dedicated Windows drive. None of these solutions did the trick, but yours did. In my case, at the BIOS screen I hit F12 (Gigabyte motherboard) to select boot drive (faster than changing boot order). Windows booted directly, rather than through Chimera/Chamelon bootloader on my OSX drive… and the rest was smooth sailing. Thanks!
[Reply]
Andreas Reply:
April 24th, 2013 at 7:57 am
Thanks mate. Good hint, since I run the same setup…
[Reply]
Nov 7th, 2011 at 12:56 pm
In my case i had to disable anti-virus soft. Thanks a lot
[Reply]
Dec 11th, 2011 at 8:40 pm
Same solution as Sprewell. I am dual booting a hackintosh build on a separate disk. Just unplugged the power from the OSX disk and everything installed fine.
[Reply]
Jan 31st, 2012 at 10:51 am
Just the info I was looking for. Great. Thanks!
[Reply]
May 13th, 2012 at 11:18 pm
Same issue as Sprewell. I’m dualbooting Windows 7 and Ubuntu 12.04, and this is the first time I got this error message. I tried “mountvol /E” but it didn’t work. I then read Sprewell’s comment and changed the hard drive order in the boot sequence from BIOS, and it worked. I’m using two SSDs, one with Windows 7 and one with Ubuntu. So just make sure Windows boots first.
[Reply]
Alex Reply:
August 8th, 2012 at 5:18 pm
EliasAlucard , how You fix the grub problem ?
[Reply]