Microsoft issued a formal apology on Friday and reported “broad recovery and stability across our services,” bringing Outlook, Teams, and Microsoft 365 back online after a global outage that lasted roughly 18 hours across 74 countries. For the more than 430 million people who use Microsoft 365 apps, delayed emails will still reach their inboxes after Microsoft extended its message delivery timeout window to 48 hours while clearing backlogged queues, according to Fox Business.
Mailboxes, Teams calls, Word, Excel, PowerPoint, OneDrive, and SharePoint began recovering just before midday GMT on Friday, though Microsoft brought capacity back in stages so recovering servers would not crash again under heavy traffic. On Wall Street, Microsoft stock dipped 1.1% to $516.86 at the open on Friday before rebounding to close up 0.2%.
“We are deeply sorry for the disruption this incident has caused,” Microsoft said in a statement on X, adding that the outage was “a technical issue not related to cyber or AI / agents”. Charles Lamanna, Microsoft’s executive vice president of Copilot, Agents, and Platform, whose organization oversees Exchange Online and Teams infrastructure, also posted on X: “We regret that today’s outages caused disruptions for our customers, and we are working to address the issue,” noting there was “no indication this is the result of malicious or cyber activity”.
Why is Microsoft still down for some users
Even after broad recovery began on Friday, some organizations saw lingering delays because Microsoft “restored services gradually, validating stability at each stage,” the company said. Microsoft explained that the failure “was introduced by an issue during an earlier network capacity upgrade that surfaced following a recent network change,” causing servers that keep Microsoft 365 running to fail automated checks and become unexpectedly unavailable.
Because the restoration rolled out across regions in stages, outlets measured the outage window differently. The Guardian and Windows Latest reported an 18-hour outage from Thursday evening until just before midday GMT on Friday, while a separate Guardian report noted residual disruptions stretched past 21 hours for some users. Cybersecurity firm NeuralTrust logged the initial Exchange Online degradation (EX1550543) starting at 16:17 UTC on Thursday and calculated more than 15 hours for the primary Microsoft 365 incident (MO1550821), which opened at 18:26 UTC Thursday before recovery began at 10:01 UTC Friday. System administrators tracking their tenant status were directed on Microsoft’s Q&A forum to check the Microsoft 365 admin center Health dashboard.
Mark Gregory, an associate professor in the School of Engineering at RMIT University in Melbourne, told The Guardian that the fault hit the network layer in Microsoft’s infrastructure and resembled the configuration failure that knocked out Australian telecom carrier Optus in 2023. When part of a server pool fails configuration checks, customers are pushed onto a smaller group of remaining servers. “If you lose part of that pool, then all of the users are trying to access the remaining servers, and that overloads them. And then they go down. And so you end up with a cascading problem. Then it takes time to find the underlying problem, in this case, a misconfiguration in the network layer,” Gregory said.
AI connectors and public services recover worldwide
The outage spilled over into third-party AI tools that plug into workplace accounts. More than 90% of Fortune 500 companies use Microsoft’s Copilot chatbot, which went down alongside Microsoft Defender XDR. OpenAI logged degraded performance for ChatGPT’s Microsoft connectors starting Thursday at 1:29 p.m. ET, warning that new connections could break and connected tools might fail. Anthropic also reported degraded performance on its Microsoft 365 connector, Claude for Outlook, claude.ai, and Claude Cowork due to the upstream failure, while the Claude API, Claude Code, and Claude Console stayed operational. Both OpenAI and Anthropic said those connector problems began subsiding on Friday afternoon.
Government offices, hospitals, and police forces in the US and UK began clearing backlogs on Friday after relying on phone and in-person workarounds. In the US, the House of Representatives chief administrative officer sent a campus-wide alert to congressional staffers on Thursday, the City of Tampa posted an outage notice on its municipal website, and the Arapahoe County Sheriff’s Office in Colorado had to process inmate bond payments in person while Outlook email was offline before reporting Friday that email and online processing had returned. Police in Greensboro, North Carolina, also confirmed on Friday that their department email was working again. In the UK, National Rail warned passengers they might not be able to open emailed train tickets, police forces asked the public to report crimes by phone, hearings were delayed at Manchester’s Minshull Street Crown Court and the Scottish Courts and Tribunals Service, and NHS staff lost access to Outlook, Teams, SharePoint, and OneDrive before doctors began sending and receiving emails again Friday afternoon. UK Cyber Minister Baroness Elizabeth Lloyd said the outage mainly hit back-office email and messaging, leaving 999 emergency calls and NHS 111 lines running.
Across Asia-Pacific, Indian airlines IndiGo and Akasa Air reported disruptions to email customer support, Taiwanese security firms, life insurers, and investment trusts reported fund management delays, and Japanese shipping company Sagawa Express paused online airport and train station reservations while pharmaceutical maker Taisho took orders by phone. As background, Downdetector logged nearly 130,000 problem reports after the outage began Thursday, including more than 97,000 for Outlook alone, and Australia activated a priority-restoration cyber deal with Microsoft on Friday as risk advisory firm RSM Australia estimated billions of dollars in economic costs across government agencies, courts, and clinics, though the Australian Medical Association reported no impact on patient care.
Prior cloud disruptions and next steps
In separate background, the Microsoft 365 failure marked the company’s second global cloud outage in two months, following an October 2026 Azure platform outage that disrupted workplace software across multiple industries, shortly before Microsoft posted $92.3 billion in quarterly revenue after offering buyouts to 60,000 employees. Microsoft said it will “provide a full post-incident report once our review is complete”.