Microsoft said it was "deeply sorry" for a widespread outage that disrupted services for millions of users and organisations worldwide, adding that it had "addressed the underlying issue". The company determined that servers were "unexpectedly unavailable" because of a problem that caused them to fail during automated checks. The outage began Thursday evening and lasted roughly 18 hours before services started to recover just before midday GMT on Friday. Microsoft said the disruption was a "technical issue" unrelated to cyber-attacks or AI agents, and that it was bringing services back gradually to ensure stable restoration.
The outage affected Microsoft 365 services used by more than 430 million people globally, and services including Microsoft Teams, Outlook email, Word, Excel and PowerPoint were impacted. Enterprise services such as SharePoint and OneDrive, along with Copilot, Microsoft's AI chatbot, were also affected. Down Detector showed nearly 130,000 reports of problems across 74 countries at around 6pm GMT on Thursday. More than 90% of Fortune 500 companies use Copilot, according to the company. Charles Lamanna, Microsoft's executive vice-president of Copilot, said: "We regret that today's outages caused disruptions for our customers, and we are working to address the issue."
The outage disrupted critical services across multiple countries. In the UK, healthcare systems were affected and several police forces asked people not to report crimes online but to phone instead. Some schools notified parents that attendance reporting had to be done by phone. National Rail warned people might not access emailed tickets. In the US, government offices including congressional chambers that rely heavily on Outlook email were hit, and law enforcement offices across the country reported problems. One sheriff's county in Colorado said it could not process bond payments because Outlook was down. Multiple US cities posted notices about the outage on their websites.
Global impact extended beyond government and healthcare. In Australia, the risk advisory firm RSM Australia said the outage was expected to cost billions of dollars. Several government agencies, including national security services, were unable to access or send emails. Hospitals and health clinics were affected, although the Australian Medical Association said there had been no impacts for patient care. In Japan, shipping company Sagawa Express could not accept online reservations for some services, and pharmaceutical company Taisho had to handle orders by phone. Indian airlines IndiGo and Akasa Air reported disruptions to email support services. In financial markets, some portfolio managers were unable to check emails, making it difficult to access some trading platforms.
When Wall Street trading opened, Microsoft shares dipped 1.1% to $516.86. The outage also affected connectors used by OpenAI's and Anthropic's AI services. OpenAI said it was investigating a problem with Microsoft connectors in which new connections might be broken and tools were not working as expected. Anthropic identified an issue with an upstream provider affecting its Microsoft 365 connector. This outage followed a previous incident last month when Microsoft reported an outage of its Azure cloud platform affecting productivity software and industries worldwide.
Mark Gregory, an associate professor in the School of Engineering at RMIT University in Melbourne, said the outage appeared to affect the network layer in Microsoft's systems, potentially similar to a configuration issue that brought down Optus's network in 2023. He explained that when servers have configuration issues, customers are forced to share a smaller pool of servers, and if part of that pool is lost, all users trying to access the remaining servers overload them, creating a cascading problem. Gregory said businesses reliant on cloud services such as Microsoft 365 should have backup options.