A glitch in Microsoft Corp.’s network has disrupted the work of businesses and government agencies in more than 70 countries.

The bug, which reared its head on Thursday around 12:35 p.m. ET, knocked the company’s popular Exchange Online platform offline. Organizations use the cloud service to store employees’ inboxes and calendars. Microsoft has still not fully restored its infrastructure.

Deployments of Exchange Server, a version of the platform that users run on-premises, are not affected. However, the outage did disrupt a number of Microsoft Teams and Microsoft Copilot 365 features that rely on data from users’ Exchange inboxes. Intune, a tool that administrators use to manage employee devices, is also experiencing technical issues.

The outage has impacted numerous companies worldwide. Workhorse Group Inc., an electric vehicle maker, pushed back its earnings call from today to Monday. Shipping giant Maersk and stock exchange operator Euronext notified customers that they’re experiencing communications issues.

The public sector is also impacted. Several U.S. municipalities reported technical problems, while a number of court cases had to be delayed. In the UK, the National Pharmacy Association warned that the Exchange Online outage may slow prescription processing. Hospitals, public transportation agencies and schools are affected as well.

The operator of Downdetector, an outage tracking service, received downtime reports from hundreds of thousands of users.

Parts of Microsoft’s infrastructure started recovering early this morning. In an update published at 2:30 a.m., the company stated that it was seeing “positive results” after patching an “upstream authentication/routing configuration” module. About three hours later, Microsoft’s systems in the Asia Pacific region began regaining service access. North America and Europe followed suit shortly there.

Microsoft shared its first explanation of what went wrong around noon today. “The incident was introduced by an issue during an earlier network capacity upgrade that surfaced following a recent network change,” the company explained. “We have addressed the underlying issue and continue to restore service to remaining customers and regions.”

Microsoft added that the outage wasn’t caused by a cyberattack or AI agents.

The company’s status page indicates that infrastructure restoration work is still ongoing. As a result, some users may have trouble accessing Exchange Online and certain Microsoft products that interact with it. The company is monitoring the backlog of emails that piled up while the service was offline to ensure no data loss occurs.

Microsoft plans to release a detailed technical report about the outage once all its services are fully restored.

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