In an unusual step Microsoft chief executive Steve Ballmer has been criticising his own products, notably Windows Mobile.
Ballmer said at Microsoft's Venture Capital Summit that Windows Mobile should be on version seven by now and that the company had "screwed up", according to one participant.
Journalists are banned from the event but venture capitalist Paul Jozefak sent a tweet from the event floor during Ballmer's address to delegates.
"Ballmer said they screwed up with Windows Mobile. Wishes they had already launched WM7. They completely revamped the team," the message read.
Windows Mobile 6.5 is due out in October and Microsoft hopes to get version seven out by next year, according to company executives.
Windows Mobile is facing something of a crisis after Motorola and Palm decided to stop producing handsets using the operating system, while Apple and RIM have growing market share in the crucial smartphone market and Intel's Moblin system will be coming online soon.
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