Microsoft Corporation has fully restored access to its cloud and work products, including Outlook, Teams, and the Copilot AI tool, after a large-scale outage that lasted more than 20 hours and paralyzed the work of companies and government agencies in more than 70 countries around the world.
Microsoft Corporation has fully restored access to its cloud and work products, including Outlook, Teams, and the Copilot AI tool, after a large-scale outage that lasted more than 20 hours and paralyzed the work of companies and government agencies in more than 70 countries around the world.
The outages began around 1 p.m. ET on Thursday and continued through Friday. According to Downdetector, hundreds of thousands of users have complained about being unable to access email, calendars and web pages in Microsoft 365, which has more than 450 million commercial customers.
The company itself reported that the technical error occurred during a planned network bandwidth expansion. Insiders reported that Exchange servers (the basis for mail and calendars) quickly exhausted available resources and stopped responding. Engineers suspected that the program was mistakenly directing traffic to databases instead of local storage, or that the cause was an incorrect configuration of the Azure network.
More than 1,000 engineers, led by cloud chief Scott Guthrie and vice president Charles Lamanna, were involved in the response via video conference. Microsoft stressed that the incident was not related to cyberattacks or the work of artificial intelligence algorithms.
James Ferriman, a professor of computer science at the University of Reading, explained the recovery time as a cascading effect: when one server goes down, its load is transferred to neighboring servers, while millions of smartphones and laptops are constantly trying to reconnect. Because of this, the system cannot be restarted instantly - services have to be brought up gradually.
“I don't remember a business email outage ever taking this long to recover,” said Gergel Orosh, a former Skype and Uber lead engineer, calling the incident perhaps the most disruptive to business correspondence in history.
William Blair & Co. analyst Jason Ader noted that the disruption is unlikely to hit Microsoft's position immediately due to the complexity of migrating corporate processes, and the tech giant's shares have barely reacted to the news. However, in the long term, businesses may look more actively at competitors - for example, Google Workspace or new work solutions from Anthropic, presented earlier this week.
Recall that the failure of key Microsoft services affected, in particular, the Ukrainian offices of global technology companies . dev.ua's interlocutors in the Ukrainian office of EPAM reported that Outlook mail was not working in them, but the Teams messenger continued to function stably.
