A spokeswoman with Microsoft's PR firm said that all power to the main campus in Redmond has been restored. Two satellite offices in the Puget Sound area -- Eastpointe in Issaquah and Alstom in the Bellevue/Northup area -- are still without power.

All of the company's "mission critical functions" remained on line during the outage "due to a backup power system that executed without incident," the spokeswoman said.