Two analysts Thursday accused Microsoft Corp. of changing the meaning of "release candidate" by pushing out a version of Windows Vista that still needs major work.

Microsoft, which is rushing to meet Vista deadlines of November for corporate customers and January 2007 for others, dubbed a recent build of the operating system as Release Candidate 1 (RC1). Last week, the Redmond, Wash. developer made RC1 available to a small group of outside testers; this week, it posted the update to its download site for users of Vista Beta 2.

But analysts say Microsoft's doing more than rushing development, it's pushing the terminology into uncharted territory.

Joe Wilcox, an analyst with JupiterResearch, said that Microsoft's corrupted the term.

"'Release candidate' is a long-standing term, it has meaning behind it," said Wilcox. "The name says it all. This should be code that's ready to release." It's not, said Wilcox. And Microsoft told him so.

"I was told that Microsoft recognizes that it has plenty of work still to do on Windows Vista and that Release Candidate 1 is not a near-final version," Wilcox went on. "I was told that Microsoft's approach, perhaps, definition, of a release candidate had 'evolved.' I countered that Microsoft had changed the definition."

Michael Cherry of Kirkland, Wash.-based Directions on Microsoft agreed that Microsoft's misused 'release candidate.'

"They've completely messed up the vocabulary," he said. "What exactly is a pre-release candidate?" he asked, referring to the term Microsoft used last week to describe a publicly-available build of Vista that immediately preceded RC1. "What they released [as RC1] would in the old vocabulary be a Beta 3."

Cherry said he had installed RC1, but immediately had several bugs to report. "Someone like me shouldn't be submitting four new bugs on a build called 'release candidate,'" he said.

But does it matter, really matter, what Microsoft calls a preview Windows build?

Both analysts said it does.

"People are trying to evaluate whether [Microsoft] is going to make its dates or not. Analysts, the media, PC makers, software developers, businesses, consumers, everyone," said Wilcox. But if the two sides -- Microsoft on one, everyone else on the other -- aren't in sync, it leads to confusion, or worse, said Wilcox.

"Is this good enough to release, or does Microsoft need to make changes before it's ready?" he said. "Those are two very different starting points."

For his part, Wilcox isn't buying 'release candidate' for the version of Vista that Microsoft's pegged as RC1. "This is a work in progress, and I think that two release candidates will be necessary."

In turn, that means he's not as confident in Microsoft making the January release as he was before the Redmond, Wash. developer put the RC1 label on last week's build.

Neither is Cherry. "It isn't ready," he said flatly.

Nor is Microsoft fooling anyone by applying 'release candidate' to this build of Vista. "Watch the source here, who's calling this 'release candidate," Cherry said. "It's Microsoft. They're going to be overly optimistic to make it appear they'll make their dates."