DaMan writes "According to the site WindowsSecrets, the stealth Update that Microsoft released back in August isn't quite as harmless as the company claims. The site's research has shown that when users try to do a repair to XP subsequent to the update, bad things happen. 'After using the repair option from an XP CD-ROM, Windows Update now downloads and installs the new 7.0.600.381 executable files. Some WU executables aren't registered with the operating system, preventing Windows Update from working as intended. This, in turn, prevents Microsoft's 80 latest patches from installing -- even if the patches successfully downloaded to the PC.' ZDNet's Hardware 2.0 has independently confirmed that this update adversely affects repaired XP installations: 'This issue highlights why it is vitally important that Microsoft doesn't release undocumented updates on the sly. Even the best tested update can have unpleasant side-effects, but if patches are documented properly and released in such a way that users (especially IT professionals) know they exist, it offers a necessary starting point for troubleshooting.'"