NEW DELHI: A global Microsoft 365 outage disrupted operations across offices as Outlook email, Teams calendars and the tools that connect ChatGPT and Claude to Microsoft’s workplace services remained paralysed.The problem, which started late Thursday (India time), was partially restored on Friday evening though intermittent issues persisted. By late evening in India, Microsoft said mailbox access was improving, and delayed emails were being processed, while stating that it had found no indication of a cyberattack. This was the second disruption since Oct 2025 when MS Azure services faced an eight-hour-long global outage.Companies that rely on MS services were forced to opt for other alternatives such as Slack, Webex and Zoom to keep their operations going. Tata Motors Passenger Vehicles cited the outage in a stock exchange filing and shifted its quarterly results webcast with Jaguar Land Rover executives to StreamCart. IBM reportedly moved workplace communication to Slack during the disruption. HDFC Bank told customers on X that its banking services remained available.Airlines and airport operators said operations continued while email communication with passengers was disrupted. Travellers who bought or changed tickets during the outage had to download them from the airline’s website or app if their confirmation email did not arrive. Airport operators said they were unable to send emails. Air India rerouted incoming messages, IndiGo directed passengers needing urgent help to its 6E Skai chatbot, and Akasa Air asked customers to call or use social media.Overseas, Australia’s sanctions office directed urgent enquiries to the phone. In UK, National Pharmacy Association warned that disruption to NHS email could delay prescriptions. On Thursday, Microsoft first flagged trouble accessing work mailboxes in the Americas. In India, complaints picked up mainly as offices opened on Friday.Microsoft starts reversing recent network changeOutage tracker Downdetector logged around 3,800 Outlook complaints at 10.12am, close to the overnight peak.“We regret the disruption today’s outage has caused for many of our customers,” Puneet Chandok, president of Microsoft India and South Asia, wrote on LinkedIn. “Our global teams continue to work with urgency to resolve the issue.”The problem centred on Exchange Online, the service that runs workplace email and calendars. Some servers unexpectedly went offline, leaving fewer machines to handle the same workload. Some stopped responding again when users reconnected.Microsoft began reversing a recent network change that coincided with the start of the disruption and was investigating whether it triggered the outage. Teams chats and calls could still work even when calendars and meeting invites failed.Anthropic said most email, calendar and search requests through Claude’s Microsoft 365 connector were failing. Some users could not open Claude for Outlook, while others had trouble performing mail and calendar tasks. OpenAI said ChatGPT users could have trouble setting up new connections to Microsoft services and that some existing connections were also failing.Anthropic separately investigated sign-in errors affecting Claude.ai, Claude Code and its developer platform. It began investigating at 3.28pm IST and said at 4.35pm that it had deployed a fix and was monitoring recovery.