The European Commission (EC) has received assurances from Microsoft chief executive Steve Ballmer that its forthcoming Windows 8 operating system will allow rival browser manufacturers to run their tools on the new platform.
According to Reuters, competition commissioner in the EC, Joaquin Almunia, said at a conference in Italy on Saturday that he has spoken with Ballmer and was satisfied the firm was aware of its obligations.
"In my personal talks with Microsoft chief executive Steve Ballmer he has given me assurances that they will comply immediately regardless of the conclusion of the anti-trust probe," he said.
"[It's] a very, very serious issue."
The concerns relate to issues raised by rivals such as Google and Mozilla that Windows 8 on ARM, known as Windows RT, would only be able to support the Internet Explorer (IE) browser when used in classic mode.
This would go against the current situation where all rival browsers are offered to Windows users on via a browser ballot system agreed to by Microsoft in 2009. The ballot is intended to avoid any competition concerns raised by the native installation of IE on Windows.
Microsoft is currently under investigation from the EC on an issue related to this agreement, after it came to light that the browser ballot system was removed from millions of computers due to a software update in February 2011.
The software giant could face a fine totalling up to $7bn if hit with the full extent of the EC's powers.
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