Researchers are claiming that Microsoft has started updating files on end users' computers running Windows Vista and XP, even when the automatic update feature has been disabled. Scott Dunn, an editor at the Windows Secrets newsletter, said that nine files in XP and Vista -- but not the same files in each operating system -- have been changed by Windows Update, the Microsoft update mechanism, without displaying the usual notification or permission dialog box. The files, said Dunn, are related to the XP and Vista versions of Windows Update (WU) itself.

In recent days, Windows Update (WU) started altering files on users' systems without displaying any dialog box to request permission. The only files that have been reportedly altered to date are nine small executables on XP and nine on Vista that are used by WU itself. Microsoft is patching these files silently, even if auto-updates have been disabled on a particular PC.

It's surprising that these files can be changed without the user's knowledge. The Automatic Updates dialog box in the Control Panel can be set to prevent updates from being installed automatically. However, with Microsoft's latest stealth move, updates to the WU executables seem to be installed regardless of the settings - without notifying users.

When users launch Windows Update, Microsoft's online service can check the version of its executables on the PC and update them if necessary. What's unusual is that people are reporting changes in these files although WU wasn't authorized to install anything.

This isn't the first time Microsoft has pushed updates out to users who prefer to test and install their updates manually. Not long ago, another Windows component, svchost.exe, was causing problems with Windows Update, as last reported on June 21 in the Windows Secrets Newsletter. In that case, however, the Windows Update site notified users that updated software had to be installed before the patching process could proceed. This time, such a notice never appears.

For users who elect not to have updates installed automatically, the issue of consent is crucial. Microsoft has apparently decided, however, that it doesn't need permission to patch Windows Updates files, even if you've set your preferences to require it.