Microsoft has pulled yet another update for the Windows 7 operating system after it released a patch that blocked users from installing new graphics drivers, other Windows updates, and disabled the Windows Defender anti-malware protection.

The company released the KB3004394 update on December 10 in order to reset how Windows updates root digital certificates used to authenticate SSL and TLS connections.
After the patch is applied, Windows 7 now polls for certificate updates once a day rather than once a week.
However, the change resulted in users of Windows 7 Service Pack 1 as well as Windows Server 2008 R2 Service Pack 1 being unable to to install drivers from graphics card vendors AMD and Nvidia.
Some other Windows Updates, as well as some third-party software, were also blocked. A number of users reported spurious User Access Control prompts appearing on their operating systems and the VirtualBox virtual machine ceasing to work after the patch was applied.
The patch also appears to have affected Windows Defender, preventing the security product from starting.
"We have found that this update is causing additional problem on computers that are running Windows 7 Service Pack 1 (SP1) and Windows Server 2008 R2 SP1. This includes the inability to install future updates," Microsoft said in an advisory.
Microsoft quickly issued a new update to address the bad patch and withdrew the original for Windows 7. It continued to recommend the update for Windows 8.1, Windows RT 8.1, Windows Server 2012 R2, Windows 8, Windows RT, and Windows Server 2012.
"The KB 3004394 update does not cause any known problems on the other systems for which it is released. We recommend that you install the update on the other systems," Microsoft advised.
It's the latest in a line of several updates Microsoft has pulled this year.
In August Microsoft was forced to pull a Windows security update after customers reported blue screens of death and reboot loops.
Just last week Microsoft removed a patch for Exchange Server 2010 after discovering it caused issues in connectivity between the Outlook client and mailboxes.