A major global outage of Microsoft services has caused problems or, in some cases, disabled entire services, including email and artificial intelligence products. Microsoft stated that the outage was not caused by a cybersecurity incident, but attributed it to 'increased load' on its infrastructure. Efforts to resolve the issues have so far been largely unsuccessful, and the full scale of the outage has not been confirmed.
Microsoft 365 services, including Teams, Outlook and Microsoft's artificial intelligence software Copilot, were affected by 'connection issues'. Users reported varying levels of access - many were unable to send or receive email, view certain files or details in their calendars. Some users were able to use Teams and utilised messaging and online meeting functions without issue. More than 430 million people use Microsoft 365 applications according to Microsoft's website.
Monitoring website Downdetector recorded 140,000 people from 74 countries who reported problems with Outlook on Thursday evening. The actual number affected is likely much higher as Downdetector relies primarily on user self-reporting. Microsoft 365 is also used by businesses worldwide and is expected to have a knock-on effect on other services. Tech giants OpenAI and Anthropic reported problems as a result of the outage. OpenAI, the creator of ChatGPT, stated that it was investigating an issue affecting its connections to Microsoft's services, which caused some tools to not work as expected.
From US city administrations to Australian intelligence agencies, disruptions worldwide were widespread. Courts from Los Angeles to Texas warned that communication could be delayed. In Canada, public broadcaster CBC reported that a health network managing several hospitals in Toronto had email problems, but that patient care was not affected. The Japanese government also stated that its joint IT platform had been disrupted. Across the United Kingdom, general practices, pharmacies, police and schools were affected by the outage. Some general practices called on patients not to send messages via their websites until the problem was resolved. Several large police forces are urging citizens to call if they wish to file a report.
Microsoft ruled out a cyberattack and attributed the current outage to 'increased load' on its infrastructure. The term refers to a situation where servers are subjected to a much higher volume of stress than usual. In the case of Microsoft's outage, a large number of servers became 'unexpectedly unavailable', the company stated, which sent additional traffic to the remaining servers, overloading them. On Friday afternoon, Microsoft stated that it had seen 'encouraging progress in recovery' in Europe and improvement in North America. The company added that it was focused on 'resolving remaining areas of disruption' and warned that 'some users may still experience intermittent issues as recovery actions continue'. In a later statement, the company stated that it continued to see improvements 'with email queues significantly reduced and approaching normal levels'. Although Outlook email service appears to be returning for some, the outage has lasted more than 20 hours so far - in outage terms, this is considered a long time.
Professor James Ferryman from the Department of Computer Science at the University of Reading stated that the details published by the company provide some clues. 'What Microsoft has told us is that part of its servers establishing secure connections are being overwhelmed, and when that happens, the server simply stops responding', Ferryman said. 'The problem is that this type of failure grows like a snowball', he added. 'One server falls, its workload is transferred to the next, and in the meantime a huge number of phones and laptops are constantly trying to reconnect.' 'You cannot just switch everything back on at once. You have to bring it back part by part', he concluded. The challenge is therefore not just fixing the failure, but managing the huge influx of devices trying to reconnect once services begin to come back online.
Gergely Orosz, a former lead software engineer at several large tech companies including Skype and Uber, stated that this could be the 'most devastating' business email outage 'of all time'. Orosz stated that it is still difficult to know how many people are affected by the disruption, but added that he 'cannot remember' a business email outage lasting this long to return to normal. Australian cybersecurity expert Troy Hunt told the BBC that the outage could have far-reaching consequences. 'Microsoft is a huge part of the internet's backbone and reminds us how critical email still is', Hunt stated. 'This outage affects not only many people's ability to work, but also things like the ability to communicate about appointments, purchasing items that require verification, creating or accessing accounts and services', he added.
