A widespread Microsoft 365 outage on Thursday disrupted the ability of popular AI assistants, including ChatGPT and Claude, to access users' Microsoft work data. While the core AI applications remain functional, the integration tools that connect the assistants to workplace files have been impacted.
The service disruption stems from the Microsoft 365 connectors, which allow the AI tools to read Outlook emails, calendars, Teams chats, and SharePoint files. Because this data is hosted on Microsoft's servers, the connectors stopped functioning once those servers encountered failures.
Impact on OpenAI and Anthropic
OpenAI's status page indicated elevated error rates for its Microsoft 365 connector, warning users that new connections may fail and related tools might not work as intended. Similarly, Anthropic reported issues affecting Claude—including the Claude for Outlook add-in—and attributed the disruption directly to Microsoft's incident.
Anthropic noted that its API and Claude Code continued to operate normally. However, claude.ai experienced degraded performance, though the company did not explicitly confirm if that specific slowdown was tied to the Microsoft outage.
Microsoft's Response
Microsoft attributed the underlying outage to overloaded software responsible for handling secure connections, clarifying that the incident was not the result of a cyber attack. Affected users have been advised to monitor the respective status pages of OpenAI, Anthropic, and Microsoft for further updates as services are restored.
