London workers have been locked out of Outlook and Teams as a Microsoft outage passes 10 hours, with the company saying its attempts to fix the problem are not working as expected.
The downtime has affected Outlook, Teams, and AI software Copilot, with connectivity issues persisting for more than 10 hours.
The number of outage reports for Outlook alone peaked at around 140,000, according to Downdetector, although the figure has since dropped to 28,000.
Microsoft, whose 365 apps are used by more than 430 million people, has said its attempts to address the problem are not “taking as expected”.
The company added that the outage was due to “elevated load” on its infrastructure, and not a cyber-security incident.
The knock-on effect has been reported by other tech companies, including OpenAI and Anthropic.
The outage has affected users in at least 74 countries worldwide, causing disruptions to businesses and government systems.
The company has said it is seeing “partial recovery” across regions.
For London, the timing could hardly be worse. The outage struck on a working morning, leaving office workers across the capital unable to send or receive email, join video meetings, or access shared files through Microsoft’s cloud services. With hundreds of thousands of people in the City, Canary Wharf and across London’s business districts relying on Outlook and Teams for their daily work, the disruption has rippled through firms large and small.
The incident is the latest in a series of major cloud outages to hit London users. Earlier this year, a Google Cloud outage left Revolut and other services down across the capital, while European regulators demanded answers after a separate Google Cloud failure.
Microsoft has not given a time for full recovery. Users are being advised to check the company’s service status page for updates as the fix continues.
