Yankee Group has been forced to retract a report on virtualization after several inaccuracies were reported. The research company has already withdrawn the report from its website.

Virtualization vendor, VMware objected to a number of inaccuracies in the virtualization report, which seemed to favor its competitor Microsoft. The report still being carried on Microsoft's site, although VMware has asked Microsoft to remove it from there too - as yet, this requested has not been responded to.

VMware said it didn't "send the mob guys" around to Yankee Group and that the analyst had removed the report, Virtualization Price War: VMware's Little Big Horn? from its website.

The complaint centers on the comparisons that were used. VMware said the report didn't compare "apples with apples" in technology terms as it lined up Microsoft's hosted Virtual Server functionality and pricing with its "bare metal" offering instead of with VMware Server. The report also doubled counted licensing costs on VMware implementations and contained inaccuracies in its price list by failing to list VMware's bundle options and it's a la carte pricing compared with those of its rivals, VMware claimed.

Reza Malekzadeh, EMEA senior director for products and marketing at VMware told Techworld: "The tone is not what I would have used. Right now it is easy to bash VMware with claims that we are expensive and not listening to customers. But that is not what we hear from our customers. Instead the message we get back is that we provide adequate value, that VMware adds value to the business and that they usually get ROI in less than one year."

"The report is looking at market conditions, and is fairly accurate that we are seeing rapidly maturing market. Having more competition shows our vision is more correct and we always welcomed competition but such reports should give a proper view and we support correct and actual comparisons. In general people always go after the leader that's why we're under attack but we're sticking to our vision."

Malekzadeh said he'd had no assurances on when the report would be corrected.

Microsoft said: "This Yankee Group Report delivers a detailed overview of the prices and features of the major virtualization solutions to help corporate customers make informed purchasing decisions. To ensure that our customers have the most accurate, unbiased and current information, Yankee Group conducted primary research and received no vendor sponsorship for this research."

It's not clear how the report was funded. Yankee Group has not responded to several requests for information on who paid for the report or how the inaccurate figures came to be compiled.