Microsoft outage hits OpenAI and Anthropic: how did it get so bad?

A global Microsoft outage disrupted Outlook, Teams, and Copilot on Friday, affecting businesses and government agencies while also breaking Microsoft-connected features in OpenAI's ChatGPT and Anthropic's Claude. The disruption began Thursday and lasted over 12 hours, with Downdetector recording more than 130,000 problem reports for Outlook in the US at its peak. Microsoft traced the issue to unavailable servers and overloaded connection-handling processes, though a final explanation is pending. Users reported missing emails, failed logins, and difficulty accessing workplace services. The outage cascaded from Exchange Online into Teams and Copilot, and reached AI assistants through Microsoft connectors, affecting calendar access and AI tools' ability to retrieve work-related information. The incident exposed vulnerabilities in single-provider dependencies, with financial institutions in Taiwan delaying transactions and Indian airlines reporting disrupted customer support. Microsoft reported partial recovery but had not confirmed full restoration. Analysts noted that repeated incidents could push enterprises to reconsider concentrating communication, security, and AI tools with one vendor, though Microsoft's stock closed up 0.36% on Thursday.