Overview
- A multi‑day outage began when users reported trouble accessing Exchange Online around midday on Thursday, November 12, and escalated as remaining servers were overwhelmed by the extra load.
- Microsoft paused deployments, redistributed traffic, restarted servers and rolled out automated recovery tools that detect and reboot non‑responsive machines as part of its mitigation work.
- The disruption spread to more than 70 countries and produced large spikes in user reports, with Downdetector logging roughly 130,000 Outlook complaints at the peak, and it affected governments, courts, airlines and businesses.
- Microsoft said it found no evidence of malicious activity, extended email queuing to preserve delayed messages, and confirmed full restoration of services on Saturday, November 14.
- The company will publish a technical post‑incident report describing root cause and preventive steps, a disclosure that highlights wider concerns about single‑vendor dependency after similar infrastructure failures such as the CrowdStrike incident in 2024.