The main change in WGA Notifications is a new category of results for PCs with Windows installations of questionable validity.

The change addresses a problem raised by the other half of Microsoft's anti-piracy program, WGA Validation, which was introduced in mid-2005. PCs that were scanned by WGA Validation and failed to prove to Microsoft's satisfaction that they were running non-counterfeit copies of Windows XP were formerly labeled as "non-genuine" by Microsoft.

That caused WGA Validation to disallow access to certain Microsoft software, and WGA Notifications to send periodic messages asking users to reinstall XP or buy a legitimate license for it, leading to "nagware" complaints from some users.

Many users also that WGA, due to technical glitches or other issues, mislabeled their genuine copies of Windows XP as pirated. Microsoft has throughout that the rates of such "false positive" errors were very low.

At the same time, its online forum for WGA-related problems has nearly 20,000 postings from aggrieved users.