The correct sequence of events is this. In mid April 2007, Microsoft delivered a fix for Windows Update. At that time, users were experiencing issues with running Windows Update to scan for updates using Windows Installer.

"When you run Microsoft Windows Update to scan for updates or to apply updates to any applications that use Microsoft Windows Installer (MSI) 3.1 together with Windows Update, CPU utilization may reach 100 percent for prolonged periods. Additionally, you may receive the following error message in Event Viewer on a Microsoft Windows XP-based computer: application popup: svchost.exe - Application Error : The instruction at "0x745f2780" referenced memory at "0x00000070". The memory could not be "read"," informed Microsoft initially.

With a hotfix available, Microsoft was confronted with yet another problem, generated this time by the actual fix. Users which applied hotfix package KB916089 found that they could no longer install updates from either Windows Update of Microsoft Update.

"When you try to install an update from Windows Update or from Microsoft Update, you experience the following symptoms: the Svchost.exe process that runs Windows Update stops responding, you receive an access violation error. This access violation stops the Server service and the Workstation service," read the symptoms described by Microsoft.

To summarize, Microsoft issued the first hotfix to resolve functionality problems with the Svchost.exe process, and they issued an additional hotfix designed to take care of the problems generated by the first solution. The only disadvantage in this context are disgruntled users which reported that the second fix is not functional.

Complaints have been pouring on Microsoft's support forums claiming that the problem persists even after deploying both hotfixes. The latest resolve was made available at the end of the past week, and Microsoft failed to comment in the light of the new reports.