Former Microsoft co-president Jim Allchin called the company's decision to allow PC manufacturers to label machines not capable of running all of Windows Vista's features as Vista Capable "terrible" and "misleading," according to new e-mails unearthed Monday as part of a consumer fraud suit against the company.

"I believe we are going to be misleading customers with the Capable program," Allchin wrote in an e-mail to a group of Microsoft product executives. PC makers "will say a machine is Capable and customers will believe that it will run all the core Vista features," wrote Allchin, in the April, 2006 message.

Other e-mails entered earlier as evidence in the case show that Microsoft had previously lowered the specifications for a Vista Capable PC in order to appease Intel, whose 915 graphics chipset was not capable of running Vista's slick, 3-D Aero interface.

"The fact that Aero won't be there EVER for many of these machines is misleading to customers," wrote Allchin, who retired from Microsoft as soon as Vista debuted in January of 2007. He added that he felt the Vista Capable program was "wrong for customers."

The e-mails have been entered into evidence in a class action lawsuit that accuses Microsoft of deceptive marketing practices. The plaintiffs contend that Microsoft intentionally duped customers by advertising as Vista Capable computers that lacked the horsepower to fully support Vista.

The Vista Capable campaign was meant to assure PC buyers who bought systems prior to Vista's launch that they would be able to upgrade their machines to the new OS when it became available.

In their initial complaint, consumers Dianne Kelley and Kenneth Hansen claimed they were the victims of "bait and switch" sales tactics by Microsoft and filed a lawsuit against the software maker last March in federal court in Washington state. A judge earlier this year granted the case class action status.

Changes that Microsoft made to the definition of Vista Capable in early 2006, just a few months before the operating system was finalized, also irked hardware maker Hewlett-Packard. HP invested heavily in components designed to meet the original, more stringent definition, according to e-mails filed in the case.

HP developed two new motherboards specifically for Vista.

"The decision you have made and communicated has taken away an investment we made consciously for competitive advantage knowing that some players would choose not to make the same level of investment as we did in supporting your program requirements," wrote HP consumer PC executive Richard Walker, in an e-mail to Allchin and Kevin Johnson, dated Feb. 1, 2006.

In an e-mail to Microsoft CEO Steve Ballmer, Allchin called the situation "a mess."

"Now we have an upset partner, Microsoft destroyed credibility, as well as my own credibility shot," wrote Allchin. For his part, Ballmer appeared unwilling to accept any blame for the problems. "I had nothing to do with this," Ballmer wrote in an e-mail to Allchin and Johnson. "I am not even in the detail of the issues."

Microsoft has argued that it did not deceive consumers because the Vista Capable campaign distinguished between PCs that could run the basic version of the OS and those able to run the premium version. The case is ongoing.