Microsoft's Outlook Outage Hits Day Two, With No Recovery Timeline

Downdetector logged more than 130,000 US reports of Outlook problems at the peak on Thursday, as Microsoft's global outage of Exchange Online dragged into a second day with no timeline for full recovery.

The disruption, first flagged by Microsoft on Thursday around midday ET, has left users unable to access email and has knocked out Teams, Copilot, and a string of other Microsoft 365 tools. By Friday morning, Microsoft's public service status page still showed "service degradation" for both business customers and consumer products.

The blast radius extends beyond Redmond's own apps. Anthropic and OpenAI both said on their status pages that their connectors to Microsoft 365 tools are disrupted. Anthropic added that authentication issues were affecting Claude Code, though it did not attribute those problems to the Microsoft outage.

What does Microsoft say happened?

Microsoft first acknowledged the problem in an X post on Thursday, saying users in the Americas were having trouble accessing Exchange Online mailboxes. A follow-up post widened the scope: the issue could affect users "in any region."

In a 3:34 a.m. X update, Microsoft said some of its infrastructure was under elevated load across multiple regions. The strain, it said, did not come from a spike in customer traffic — a number of servers had unexpectedly become unavailable.

Microsoft also said it had "no indication" the disruption was caused by malicious activity.

The fix has been messy. Microsoft said in further X updates that it had taken steps including restarting servers. Early Friday, it cautioned that servers which initially returned to service could become unresponsive again once traffic hit them. In an 06:11 a.m. ET update on Friday, Microsoft said it had made "additional progress toward recovery," with some mailbox access and delayed email processing improving. But it warned users could still face intermittent issues.

The company has not given users a timeline for a full recovery.

How wide is the impact?

The affected list runs deep because so many products sit on Exchange Online. Microsoft said in its service advisory that the disruption could affect:

• Outlook
• Teams
• SharePoint
• Copilot
• Microsoft Defender
• Intune
• Power BI
• Other Microsoft 365 products relying on Exchange Online

Downdetector's 130,000-plus figure reflects user reports from the US peak on Thursday, not a confirmed count of affected people or businesses.

The outages have rippled through governments and corporations. Reuters reported Thursday that the US House of Representatives said the outage had affected its users. Electric-truck maker Workhorse Group postponed its quarterly earnings call because of the disruption.

Airlines have scrambled workarounds. Air India said in a Thursday X post that it had rerouted email services. IndiGo said on Friday that its email support channel was disrupted. Both carriers said flight operations were unaffected. AP reported that government agencies in Singapore, the Philippines, and Japan had reported knock-on effects.

What's the takeaway?

The outage shows how much corporate infrastructure — email, collaboration, security tooling, and now AI coding assistants like Claude Code — stacks on top of Exchange Online. Microsoft says stability is improving, but with no committed recovery time and servers still at risk of going dark again under load, businesses should plan for intermittent disruption through at least the weekend.