Microsoft's Windows Genuine Advantage (WGA) validation initiative has set off a firestorm of protest throughout the open source community after programmers uncovered a special function in the software dedicated to detecting Wine, a compatibility layer for running Windows programs in non-Windows environments.

WGA authentication is set to become mandatory for all non-critical Windows updates starting in the second half of 2005. Customers must run a program that verifies their Windows license, or they will not have access to Windows Update or the Microsoft Download Center.

Thus far Microsoft has not directly responded to accusations that it may be unfairly targeting Wine, but says the intention of WGA is to reward customers for having fully licensed copies of Windows over other operating systems, which include virtualization software like Wine.

David Lazar, Director for Genuine Windows at Microsoft, told BetaNews, "WGA differentiates the value of genuine versions of Windows XP and Windows 2000 from other operating systems, including virtualized versions of Windows, by giving them access to updates and premium content."

Although any initial impact of Wine's exclusion is minor, as Wine does not require the same patches issued for Windows, the open source community has expressed concern over updates to Microsoft Office. Legitimate copies of Office can be installed on Linux using CodeWeaver's Crossover Office, without requiring a Windows license.

For now, users can download Office updates without WGA authentication from Office Update. But in a January interview with the Microsoft Watch newsletter, Microsoft said it was considering adding Office and other software to the WGA program.

Microsoft's Lazar, however, dismissed the claims. "This is untrue. Microsoft has made no statements whatsoever indicating that. In fact, any user of an Office application, for example, could simply go to the Office Update site, and get the download they need."

"Microsoft says it will leave customers running Office via Wine a loophole: They will make most, if not all, of the Office downloads available to them on the Office Online Web site – and not require them to validate using the Windows Genuine Advantage mechanism to get them," explained Microsoft Watch's Mary Jo Foley.

"But this still does not address why Microsoft is intercepting customers running genuine Microsoft software on non-Windows systems in the first place. If the goal of WGA is to thwart piracy, as Microsoft has stated, why is Microsoft blocking all Wine users in the first place?"

Some Wine users likened the move to Microsoft's alleged plot to give customers the impression that Novell's DR-DOS was incompatible with beta versions Windows 3.1. When Windows 3.1 ran atop DR-DOS instead of the company's own MS-DOS software, users encountered bugs.

Today, over a decade later, open source advocates are fuming about error messages that are seemingly generated simply by the presence of Wine.