Microsoft 365 Outage Disrupts Outlook and Teams Worldwide, Still Not Fully Restored Friday Morning
Microsoft 365 services stopped working for users around the world starting Thursday afternoon, disrupting Outlook email, Teams and Copilot, and Microsoft had not fully restored service by Friday morning, nor said when full restoration would come.
Downdetector, a site that tracks outage reports, had received more than 130,000 reports related to Outlook by about 1:27 p.m. Thursday, Reuters reported. Reports related to Microsoft 365 topped 46,000, and Teams reports reached about 3,000. The reports came from 74 countries.
At the center of the outage is Exchange Online, the backbone of Outlook email. According to Microsoft’s service status page, users could not reach their Outlook mailboxes on the web, desktop or mobile. Email delivery slowed or stopped altogether. Microsoft has recorded the Exchange Online outage as starting at 11:17 a.m. Thursday.
Other services that depend on Exchange Online were hit as well. In Teams, calendar management, meeting scheduling and invitation processing broke down, and Copilot, the AI assistant, could not retrieve work email, calendars or files. Management and security tools including Planner, To Do, Intune, Purview and Defender were also affected.
Teams calls, meetings and chats mostly kept working, Microsoft said. Files stored directly in SharePoint, the file sharing service, could still be opened.
Microsoft said a large number of its servers suddenly became unavailable, overloading the remaining servers. The core process that sets up secure connections became overloaded, and the servers stopped responding, the company said. It is reverting a recent network configuration change that coincided with the start of the outage and is restoring servers in stages.
The company ruled out a cyberattack. Microsoft executive Charles Lamanna said it was not a cyberattack, and a company spokesperson told the Australian Broadcasting Corporation there was no sign of malicious activity. The final cause has not yet been announced.
Conditions on Friday morning were still incomplete. Microsoft’s 1:17 a.m. update still listed the service status as “Service degradation.” In the Asia Pacific region, mailbox access was improving in some areas and backlogged email was starting to be processed, the company said. It extended the email retention period to 48 hours so delayed email would not disappear.
Separately from this outage, a North America Teams outage on Thursday morning was resolved at 10:53 a.m., Microsoft said. In Japan, government information technology systems were significantly affected, the Associated Press reported.
The outage laid bare again how heavily businesses, governments, schools and airlines rely on one company’s cloud services for email and collaboration tools. Microsoft said it will publish a final root cause analysis report when the outage is over.
