US officials are investigating a complaint about Microsoft's forthcoming Vista OS according to court documents filed this week. The investigation centres on the operating system's boot-up features, although there were several other concerns highlighted.

The main complaint focuses on the ability of PC makers to customise a user's experience on their first boot up with the new OS. In particular, concerns have been raised about a new interface called the 'Welcome Center' that offers users various setup options and commercial offers. The documents were submitted Wednesday as part of ongoing efforts to ensure Microsoft complies with the final judgments of a USanti-trust case against it, which are contained in a court order from May, 2003.

Several other concerns have been raised by industry members regarding aspects of Windows Vista, but officials handling the compliance issues have not yet reached any conclusion as to the merits of those complaints..