European buyers of Windows 7 will have to download and install a web browser for themselves.
Bowing to European competition rules, Microsoft Windows 7 will ship without Internet Explorer.
The company said it would make it easy for PC makers and users to get at and install the web browsing program.
In response the European Commission expressed scepticism over the move and whether it would allay accusations of Microsoft abusing its market position.
Abusive behaviour
"We're committed to making Windows 7 available in Europe at the same time that it launches in the rest of the world," Dave Heiner, Microsoft deputy general counsel, said in a statement, "but we also must comply with European competition law as we launch the product.
"We believe that this new approach, while not our first choice, is the best path forward given the ongoing legal case in Europe."
In response the European Commission said "it would also have to consider whether this initial step of technical separation of IE from Windows could be negated by other actions by Microsoft".
In early 2008, Microsoft was fined 899m euros (£765m) by the European Commission for anti-competitive behaviour over bundling in the media player and browser into Windows.
In January 2009, Brussels reached a "preliminary view" that Microsoft was denting the chance for true competition by bundling its browser software in with its operating system.
Microsoft is due to defend itself against the charges in a hearing.
If Microsoft fails to convince the Commission that it is not harming competition could mean more fines and enforced changes to the way it does business.
"We're committed to launching Windows 7 on time in Europe, so we need to address the legal realities in Europe, including the risk of large fines," said Mr Heiner.
Windows 7 is due to be released worldwide on 22 October.
"In terms of potential remedies, if the Commission were to find that Microsoft had committed an abuse, the Commission has suggested that consumers should be offered a choice of browser not that Windows should be supplied without a browser at all," said the Commission in a statement responding to Microsoft's announcement.
It said Microsoft's approach of offering the program to computer manufacturers "may potentially be more positive" in terms of remedying its alleged abusive behaviour.
It added that if Microsoft were found to be abusing its position, the commission would have to work out if the uncoupling of IE offset that behaviour.
