Last week, Microsoft posted a slew of non-security updates for Windows 7, one of which was titled as follows: "An update is available to improve the stability and the reliability of Windows 7 and Windows Server 2008 R2." Unfortunately, according to a thread on Microsoft TechNet, the update (KB977074) is actually breaking the stability and reliability of the operating system.

"I [j]ust installed this update and my system hangs/freeze[s] at the windows bootup screen," the thread starter wrote. Another user went a little more in-depth: "At shutdown the PC often hangs with a message that a program is still running. Forcing program end does not work. The PC hangs for minutes until I press the PC’s power button. During one startup, a message came up indicating I needed to validate Windows 7. Therefore the PC lost the validation information. The revalidate succeeded. Shutdown problems consistently occur after running media center. Also have problems with recorded TV programs. Intermittently can't burn a recorded TV program to disc. After this failure occurs, a subsequent shutdown produces a hang 100% of the time."

Microsoft regularly releases Windows 7 and Windows Server 2008 R2 stability and reliability updates, and this one builds on those that preceded it. The sad part is that the issues described by the users affected sound a lot worse than the issues this update is supposed to address, like keyboard malfunctions, notification icons, and screen saver problems.

Microsoft moderator Arthur Li responded in the thread and recommended that users experiencing the issue should update their BIOS and their hardware drivers, disable any antivirus program they have installed, restart their computer with a clean boot, and try installing the update again. Nobody reported back to say whether this fixed the problem. He also marked an official answer for the thread which simply asks users to hide the update for the time being.

Ironically, users in another Microsoft TechNet thread are complaining that they cannot install this fix; for them the update process gets to 67 percent after the mandatory restart, fails, and then rolls back the changes. Li makes the same suggestions in this second thread, and even goes a little more into detail with troubleshooting, but ultimately posts the following conclusion: "you'd better wait for the next stability and reliability update."

That's not terribly satisfying advice for those suffering from the problems described above, so we asked the company for more information. "We have not seen this as a major issue within our customer support channels; however, we are aware of it and are working to identify the cause," a Microsoft spokesperson told Ars. "At this point, there is no indication that this specific update is the cause of the install issues. We will share more information when it becomes available." While we're not sure about the scope of the issue, we can say that none of our Windows 7 machines or those of our close friends have experienced the issue.

We would not be surprised in the slightest if Microsoft finds that the update in question, coupled with other factors, is in fact to blame. Users in the thread have reported that uninstalling the update manually, or using System Restore to restore to a time before they installed the update, fixes the problem for them.