At 12:30 p.m. ET on Thursday, Outlook email services began failing for both individual users and enterprise customers across the globe. By 6:00 p.m. GMT, Down Detector recorded nearly 130,000 reports of issues with the Microsoft 365 suite, which includes Teams, Word, Excel, PowerPoint, and Outlook. The incident has now lasted more than 18 hours, leaving millions unable to access their inboxes or conduct business as usual. Microsoft confirmed that a configuration update caused servers to become overloaded and taken offline. When engineers attempted to apply a fix, those servers became unresponsive again as traffic returned to them. This created a cascading effect where remaining online servers faced excessive strain, leading to widespread instability.
A Configuration Error With Lasting Consequences
Microsoft stated at 6:11 a.m. ET on Friday that there is "no evidence of malicious activity associated with this incident." The company clarified that the problem stems from a higher-than-usual stress on its servers rather than a cyber-attack. As some servers went down, traffic was funneled onto the remaining infrastructure, causing further delays. Engineers have been limiting traffic to affected locations and rolling back to earlier software configurations to stabilize the system. In an update at 9:10 a.m., Microsoft noted early signs of stabilisation but warned that service capacity had not yet returned to normal levels. Traffic is being carefully reintroduced, and health remains variable across different regions. Japan appears comparatively stable, while North America and Europe are showing improvements but still experience intermittent issues.
The recovery process has been slower than expected because servers that came back online became unresponsive when traffic resumed. This forced engineers to work through alternative solutions, extending the outage duration significantly. Microsoft extended the email timeout window to 48 hours to protect delayed messages while delivery catches up. The tech firm said it would share a full Post-Incident Report with root cause analysis after mitigation is complete. For now, the focus is on reducing email queues and backlogs while adding supporting capacity to improve service consistency. Users in Asia Pacific have seen recovery actions completed first, with mailbox access improving in those areas.
Widespread Impact Across Critical Sectors
Approximately 430 million people use these online tools worldwide, and the disruption has hit hard across multiple industries. In the UK, the NHS reported widespread and serious disruption, with staff unable to access email and IT systems. Remote therapy sessions were interrupted, and pharmacies faced significant waiting times for medicines due to communication breakdowns with GP surgeries. Several police forces urged the public to phone them instead of reporting crimes online, as digital forms were unavailable. Schools notified parents that attendance reporting had to be done via phone, and teachers could not access calendars or cloud files.
Government agencies in Australia and the Isle of Man also suffered major disruptions. Councils, courts, and state agencies told the public they were not contactable by email. On the Isle of Man, officials urged people with urgent needs to use counter services and telephone lines. The government spokesman noted that while online services were operating, confirmatory emails would be delayed. Businesses in India, including IndiGo and Akasa Air, saw their email support services affected. Financial markets experienced issues where portfolio managers could not authenticate access to trading platforms via email. In Japan, Sagawa Express could not accept online reservations at airports and railway stations, forcing Taisho Pharmaceutical to handle orders by phone.
Cyber-security adviser Jake Moore explained the bottleneck using a motorway analogy, noting that blocking one lane forces excess traffic through fewer lanes until everything backs up. He emphasized the need for contingency communication networks independent of major providers. Nicky Choo of Mimecast echoed this sentiment, pointing out that his firm built-in alternatives to prevent such disruption. Caroline Wade, a PR agency owner in Kent, described the impact on her clients as huge, particularly for time-sensitive projects like exhibition launches. Martin, a BBC listener, joked that waking up to no emails felt like bliss until he realized he needed to conclude a crucial business deal. The incident underscores how reliant modern organizations are on a few critical cloud providers, with knock-on effects that can reach far beyond simple email delays.
