A white paper by Microsoft's internal Windows product marketing team recommended that the company avoid the "Windows Vista" name on the Home Basic version of the operating system, according to documents unsealed in the Windows Vista Capable lawsuit today.

The plaintiffs in the case are citing the document to support their contention that the company wrongly marketed as "Windows Vista Capable" computers that could run only that basic version of the operating system, without Vista's signature features. Here's a key excerpt from the August 2005 white paper.

Microsoft ultimately decided to give the Windows Vista name to Home Basic, although it doesn't support Aero Glass and other features in advanced versions of the operating system.

The documents were unsealed in advance of a hearing Thursday morning on Microsoft's request for summary judgment and class decertification in the case. I've asked the company for comment, and I'll update this post depending on the response.

Update, 5 p.m.: Here's a statement from Microsoft spokesman David Bowermaster:

"The record demonstrates that Windows Vista Home Basic is an integral member of the Windows Vista family.  Microsoft developed and tested all versions of Windows Vista, including Home Basic, as part of an integrated process. All versions of Windows Vista, including Home Basic, share common improvements in security, reliability, and efficiency over Windows XP.  Ninety-three percent of the computer code in Windows Vista Home Premium is also in Windows Vista Home Basic.

"Ultimately, we provided choices to consumers, giving different options for Windows Vista Capable PCs at various price-points to meet their needs.  In tandem, we implemented a comprehensive education campaign through retailers, manufacturers, the press, and our own Web site.  This campaign gave consumers the information they needed to choose an affordable computer that would run the version of Windows Vista that best fit their lifestyle."

Microsoft also addressed the issue in its own court filing:

Plaintiffs make much of a “White Paper” from August 2005 in which some Microsoft employees proposed that Microsoft not call Windows Vista Home Basic “Windows Vista.”  O...But the White Paper gives a more balanced assessment than Plaintiffs portray.  It expressed concern that removing the Windows Vista name from Windows Vista Home Basic could create “customer confusion” because customers might think “a new PC with Home Basic did not come with the latest [operating system]” when in fact it did.  ... And what Plaintiffs cite as an argument for removing the “Vista” name from Windows Vista Home Basic actually was an argument against doing so:  when the White Paper cautioned that “customers will not likely understand or be able to articulate whether or not Home Basic and Vista Premium products are the same product or different,” it was warning about potential confusion if Microsoft did not give Windows Vista Home Basic the “Vista” name.