In a new setback to Microsoft's public sector business, the influential National Institute of Standards and Technology has banned the software maker's Windows Vista operating system from its internal computing networks, according to an agency document obtained by InformationWeek.

Staffers at NIST, a part of the Department of Commerce charged with promulgating technology standards, are scheduled to meet on April 10 in Gaithersburg, Md., to discuss their concerns about the new operating system, which Microsoft released to consumers in January amid much fanfare and to businesses in December with lesser flair.

According to the formal agenda for the meeting, NIST workers will attend a session entitled "Windows Vista Security" to discuss "the current ban of this operating system on NIST networks." NIST officials weren't immediately available to comment.

Word of NIST's Windows Vista ban comes a week after InformationWeek revealed that the U.S. Department of Transportation and the Federal Aviation Administration have both imposed similar blackouts on the operating system, as well as on Microsoft Office 2007 and Internet Explorer 7.

FAA CIO Dave Bowen told InformationWeek that he may forego upgrading the aviation safety agency's computers to Microsoft's latest offerings in favor of desktops running some combination of Linux and Google Apps, Google's new online suite of office productivity tools.

Among other things, Bowen said he is concerned that Windows Vista may be incompatible with many software applications already in use at the FAA.