Users of Microsoft’s (NASDAQ:MSFT) Hotmail and Outlook email services found themselves going without for up to 16 hours earlier this week.
The outages — caused by a firmware update that went wrong on some servers — only knocked out some users, reports TechCrunch.
In a blog post, Microsoft apologized for the outage and promised to work to prevent further problems. The outage began at 4:35 p.m. Tuesday when the company put in a firmware upgrade on some servers. While the upgrade had been performed on other servers successfully, this time it caused the temperature to rise in the servers which triggered an automated shutdown routine to protect the information on the machines.
Working straight through, Microsoft employees began restoring access for users by Tuesday evening. Final repairs were completed and full access for all was restored at 8:43 a.m. Wednesday.