Microsoft restores Outlook and other services after global outage; blames network upgrade issue

Microsoft restored its services on Saturday after a global outage disrupted Outlook and other workplace tools. The company blamed a network capacity upgrade issue, apologised to customers and said it would publish a detailed post-mortem on the incident.

New Delhi: All Microsoft products became operational on Saturday, the company’s service health page showed, after a massive global outage that disrupted Outlook email and other workplace services, with the firm saying it was deeply sorry and blamed the incident on a network capacity upgrade issue.

The page read “All products are operational” on Saturday morning, including Microsoft 365 (business or enterprise) and consumer products.

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“We are deeply sorry for the disruption this incident has caused our customers and partners. We know the trust they place in our services and take that responsibility extremely seriously,” Microsoft said in a post on X.

The company said the outage was a technical issue and was not related to cyber activity or to AI or agents. The incident was introduced by an issue during an earlier network capacity upgrade, which surfaced following a recent network change, it said.

Microsoft said it has addressed the underlying issue. Given the scale of demand, it restored services gradually and checked stability at each stage, which took longer but helped ensure a stable restoration, the company said.

“Our investigation points to technical challenges and failure modes (cascading failures + thundering herds at our network perimeter) that made recovery more difficult than normal. I’m working closely with the engineering team to complete the full post-mortem. We will publish the post-mortem shortly covering the step-by-step timeline and our many repair items to avoid similar outages in the future,” Charles Lamanna, Microsoft’s Executive Vice President of Copilot, Agents and Platform, said in a post on X.

Microsoft’s status account on X said on Saturday that it continued to observe sustained service recovery and was monitoring for an extended period because of the severity of the incident. It said it was also watching the backlog of emails built up during the outage to make sure all of them were processed before it considered the issue resolved.

The outage, which began late on Thursday, had hit Indian airlines, financial services firms, and businesses. Domestic airlines IndiGo, Air India and Akasa Air reported disruptions to email-based customer support, affecting their ability to receive or respond to some passenger queries. Air India temporarily rerouted email services to ensure customer communications continued reaching the airline, while flight operations were not reported to have been affected.

Financial services firms also faced difficulties accessing research reports and conducting client interactions.

The disruption primarily affected Microsoft 365 features that interact with Exchange Online, the company’s cloud-based email platform. Users were unable to access mailboxes through Outlook on the web and desktop applications, and email delivery was delayed.

At its peak, the outage generated more than 1.3 lakh reports of Outlook problems on outage-tracking website Downdetector, with disruptions reported across 72-74 countries.