The Microsoft Update team has announced this 'fire drill' to check that the update infrastructure runs smoothly before any real updates are delivered. A similar test run for Windows 7 beta occurred in late February.
Not all of the updates will install automatically. One of them is intended to test a new update notification feature. It will exercise the part of the update process that provides users with detailed information about updates that need to be installed manually.
Windows 7 RC users that for some reason do not wish to take part in the test of non-automatic updates will need to right-click on each of the test updates as it is presented in the Windows Update control panel and select Hide update.
May 12 will also see the arrival of a patch for PowerPoint intended to fix a 'critical' vulnerability that allows remote code execution.
Microsoft released a genuine patch for Windows 7 RC last week to fix an access control problem.