Microsoft Outage: What We Know

Microsoft has confirmed that the global outage was caused by 'elevated load' on its infrastructure, rather than a cyber-security incident.

The company said it had observed 'marginal success' in its efforts to treat the incident and is continuing to monitor activity across regions to evaluate server status.

The outage has affected tens of thousands of users worldwide, with reports of problems including emails, artificial intelligence products, and calendar apps being disabled.

The term refers to when servers are handling a much higher volume of stress than they usually do. In the case of the Microsoft outage, a large number of servers became unexpectedly unavailable, which sent added traffic to remaining servers, straining these.

Microsoft has ruled out a cyber-attack and stated that its attempted fixes were 'not taking as expected'. The tech giant said it is continuing to monitor activity across regions to evaluate server status and determine what actions it can take to improve capacity. The outage has caused significant disruptions to various services, including email and artificial intelligence products.

The full scale of the outage has not been confirmed, but monitoring website Downdetector had 140,000 people from 74 countries report issues with Outlook on Thursday evening. More than 430 million people use Microsoft 365 apps according to Microsoft's website. The software is also used by companies worldwide and is expected to have a knock-on effect to other services.

Several GP practices across the UK have warned of potential problems, with some instructing patient to make urgent queries over the phone instead of by email or web form. Tech giants OpenAI and Anthropic have both reported problems as a result of the outage.