Microsoft is gradually recovering from a service disruption that lasted an entire day, after a cascade of software failures struck a large number of its systems.
The incident began on Thursday and was initially flagged as affecting only services in the United States and the Americas region. However, as engineers struggled to restore downed servers, the problem quickly spread worldwide.
What started as an inability to use Outlook email and Teams video conferencing rapidly escalated into a full-scale meltdown, affecting Microsoft cloud services for both individuals and businesses, including email, file and document storage.
The outage also crippled the Copilot AI tool and Defender security detection software, leaving system administrators unable to log into the Intune management console or use related functions.
Some users also reported that cloud Windows virtual machines were inaccessible.
Microsoft has not yet disclosed the root cause of the failure, stating only that the incident involved "a large number of servers unexpectedly becoming unavailable," with an investigation still underway. Industries across the board have been affected.
On Friday morning on the U.S. East Coast, Outlook email services began to recover, with some messages gradually being delivered. Earlier, engineers had been unable to pinpoint what triggered the successive failures of servers in Microsoft data centers.
Doug Madory, Director of Internet Analysis at global internet traffic monitoring firm Kentik, posted on Bluesky that after roughly 18 hours of downtime, traffic to Microsoft's various services began to climb back up.
In its latest status update on Friday, Microsoft said: "There is no evidence at this time linking this event to a malicious attack."
For the millions of users who were unable to use email and online services normally on Thursday, this comes as a measure of relief. But Microsoft will still face questions about why it could not quickly fix an outage caused by its own systems.
When asked by media to verify whether it possesses technical means such as logs to detect malicious activity, and whether it has a way to reconstruct the sequence of events, a Microsoft spokesperson did not immediately respond.
The last major Microsoft cloud service incident occurred in September, when cloud services were disrupted for multiple consecutive days. Microsoft attributed that outage to a "core authentication configuration issue" that prevented users from logging into services.
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