Microsoft suffered an 18-hour outage Thursday that knocked its core cloud services offline worldwide, disrupting Outlook email, Teams video conferencing, Copilot AI and Defender security software across enterprise and consumer users.
The incident began in the U.S. and Americas before spreading globally. Initial failures in Outlook and Teams cascaded into a broader meltdown affecting cloud-based email, file storage, documents and Windows machines. System administrators lost access to Intune dashboards used to manage enterprise devices.
Microsoft disclosed only that "a large number of servers were unexpectedly unavailable" but has not publicly identified the root cause. The company confirmed no malicious activity or cyber breach was involved.
Recovery began Friday morning on the U.S. East Coast, with Outlook functionality restored after approximately 18 hours of downtime, according to internet analysis firm Kentik. Charles Lamanna, Microsoft's executive vice president for Copilot and platform, said Friday that "service availability and email delivery performance" were improving across affected infrastructure as teams investigated to prevent recurrence.
The outage marks the second major Microsoft cloud failure in six months. A September incident attributed to a "core authentication configuration" error disrupted services for days, suggesting systemic vulnerabilities in how the company architects and manages its global infrastructure.
