Microsoft completed repairs on the root cause of a more than 24 hour outage and restored service to remaining commercial customers and regions on Saturday, bringing all Microsoft 365 products back online after earlier recovering its consumer applications. The restoration ended a disruption across 74 countries and territories that hit Outlook, Teams, SharePoint and Copilot across a workplace suite with more than 450 million commercial users.
The outage began at 16:17 UTC on Thursday when an issue introduced during an earlier network capacity upgrade surfaced after a recent network change, overwhelming a core process on Exchange servers and causing returned machines to freeze again under incoming traffic. More than 1,000 engineers joined recovery calls led by cloud chief Scott Guthrie and workplace applications head Charles Lamanna as Microsoft extended its email timeout window to 48 hours to prevent delayed messages from bouncing. The company ruled out a cyberattack or AI agents as the cause and said it will release a full post-incident report.
Problem reports on Downdetector reached 19,650 a minute across five Microsoft services at Thursday’s peak, with Outlook complaints jumping to more than 2,000 times normal levels. The disruption cost up to $7B in lost productivity, according to an Anderson Economic Group estimate, forcing Britain’s National Health Service to reschedule procedures, delaying financial results at Richemont and Workhorse, halting court deadlines in Brazil and Colombia, and blocking online bond payments at a US jail.
