European Union regulators said Microsoft was offering less choice, not more, by vowing to sell the next version of Windows without any web browsers at all.
Microsoft said that it would remove its Internet Explorer browser - and not include any alternatives - in the Windows 7 software it will sell from Oct. 22 in Europe to soothe EU antitrust concerns.
The company is trying to avoid new EU fines, on top of a previous €1.7 billion fine, after being earlier charged with unfairly using its operating system monopoly to squeeze into other software markets.
But the European Commission said it preferred to see consumers offered a choice of browser, "not that Windows would be supplied without a browser at all."
"Rather than more choice, Microsoft seems to have chosen to provide less," it said in a statement late.
The EU will soon decide whether Microsoft had violated EU antitrust law since 1996 by tying the browser to its ubiquitous Windows operating system which is installed on most of the world's desktop computers.
A "must carry" option that would offer several browsers was a better option, the EU executive suggested, because "consumers should be provided with a genuine choice of browsers" on the software that manufacturers install on computers.
It said Microsoft's solution would give no choice to the five per cent of consumers who buy Windows software in a stand-alone pack, as opposed to pre-installed on a computer.
Microsoft claims the opposite, saying consumers would be free to choose whether or not to install Internet Explorer on Windows 7 and "will also be free, as they are today, to install other web browsers." It said it will give PC users who want the browser a way to obtain it.
But regulators were more positive about the larger market - which sells software to computer makers - saying Microsoft's decision meant manufacturers such as Dell could choose to install Internet Explorer or one or more other browsers.
The European Commission said it would have to weigh up whether this would actually create genuine consumer choice.
It warned that it would still have to look at "the long standing nature of Microsoft's conduct" and whether the removal of Internet Explorer "could be negated by other actions by Microsoft" - such as prompts in the system urging users to install the browser.
The EU charged Microsoft with monopoly abuse in January, following a complaint from Norway's mobile internet browser maker Opera Software ASA, which said Microsoft was unfairly using its power as the dominant supplier of operating system software to squeeze out competitors.
Opera lawyer Thomas Vinje said the decision to strip out Internet Explorer was "an acknowledgment from Microsoft that it has been breaking the law."
He said Opera would keep asking the EU to press for a "ballot screen" for new users worldwide to choose one or several browsers when they install Windows because it was the only way to restore competition.
Opera's chief technology officer Hakon Wium Lie also claimed Microsoft has held back other browsers and innovation on the internet by purposefully ignoring web standards since websites are often designed for the world's most used browser - Internet Explorer - and sometimes cannot be viewed on rival browsers.
Microsoft says it is fully compliant with web standards.
Mozilla, which makes the Firefox browser, and Google have signed on as third parties against Microsoft in the case.
Microsoft's browser is the most widely used worldwide, but Firefox is gaining in popularity and Google, the top web search provider, has released its own web browser, Chrome.Reuse content