Microsoft's unveiling of the release candidate for its upcoming Exchange Server 2010 was hit by technical problems that prevented IT professionals from downloading the software.
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Unlike other Microsoft software releases, where user demand appears to have outstripped supply, causing servers to fail, the Exchange RC, as of early afternoon Eastern time, simply appeared to be missing from the Microsoft Download Center Web site.
"We are aware of the current problem in downloading the Exchange 2010 Release Candidate and are actively working to resolve this issue for testers as soon as possible," said Michael Atalla, group product manager for Exchange, in a statement. "Thank you for your patience."
New features in the RC include support for 64-bit versions of Windows Server 2008 and Windows Server 2008 R2, and the ability for the 2010 version to "co-exist" with earlier 2007 (Service Pack 2) and 2003 versions of Exchange.
Final release is expected by year's end.
Microsoft said that its market-leading corporate e-mail server software is a nearly $2 billion-a-year business, enough, according to the software maker, to place Exchange in the top 10 of all software companies in the world if it were a standalone business.
The beta of Exchange 2010 has been tested by more than 10 million people worldwide, Microsoft said, making it the largest beta ever for a Microsoft server application.
Facing new competition from lower-cost cloud-based competitors such as Google Apps as well as a reinvigorated push from old rival Lotus Notes, Microsoft has said that Exchange 2010 will be faster and more scalable than prior versions in multiple ways.
Microsoft introduced its own hosted version, called Exchange Online, late last year. It said today that a million people are using it, up from 500,000 in November 2008.