The new investigation followslast September that Microsoft could not exclude rivals by tying its products to its near-monopoly Windows product and must allow rival software to interoperate smoothly.
One complaint was
The second was brought by an industry group,, which said Microsoft did not disclose enough interoperability information for a range of products.
"This initiation of proceedings does not imply that the Commission has proof of an infringement. It only signifies that the Commission will further investigate the case as a matter of priority," the Commission said.