Tens of Thousands Were Unable to Access Outlook, Teams, Office 365 After “Problematic Code Change”

A widespread Microsoft outage on March 1 left tens of thousands of users unable to access key services, including Outlook, Teams, and Office 365, for more than three hours. Microsoft has not provided full details on the root cause but attributed the disruption to a “problematic code change.”

Timeline of the Microsoft outage

According to Downdetector, reports of issues began rising on March 1 around 3:30 p.m. ET. More than 37,000 complaints were logged for Outlook, 24,000 for Office 365, and 150 for Teams. The majority of reports originated in U.S. cities, including New York, Chicago, and Los Angeles, though social media posts indicated the outage had a global reach.

Frustrated users turned to social media, with many initially fearing they had been hacked. “I thought I was getting my outlook hacked, turns out the entire Microsoft platform is getting hacked. Thank God it’s not personal,” one user posted on X.

Microsoft acknowledged the issue in a post on March 1at 4:34 p.m. ET via its Microsoft 365 Status account, stating: “We’re investigating an issue in which users may be unable to access Outlook features and services.”

SEE: Microsoft Patches Two Actively Exploited Zero-Day Flaws

However, the outage affected more than just Outlook; Office 365 applications such as Word, Excel, Teams, and Exchange were also impacted. In a follow-up X post, Microsoft confirmed that “various Microsoft 365 services” were down and that engineers were analyzing telemetry and customer-provided logs.

At about 5:00 p.m. ET on March 1, Microsoft confirmed it had identified a potential cause of impact, and almost an hour later reported that services were recovering. The company confirmed at 7:02 p.m. ET that service had been restored after “reversion of the problematic code change” and to “refer to MO1020913 in the admin center for detailed information.”

Users express frustration as businesses face potential losses

Despite the fix, some users continued to report issues. At 1:46 a.m. ET on March 3, the “Status Is Down” X account reported ongoing Outlook and Office 365 disruptions.

One affected customer posted on X on March 3 that Microsoft “should be ashamed of themselves” and that the continued problems are “potentially costing businesses millions of dollars.”

The company’s service status page shows all services as operational at the time of writing.

Microsoft has yet to release a detailed report on the latest outages. TechRepublic has contacted Microsoft about the cause of the initial outage and for additional information about any ongoing issues; there has been no reply at the time of writing.

Other outages that disrupted business operations

Microsoft is, unfortunately, no stranger to outages. In November 2024, Microsoft Teams experienced technical delays for over 24 hours, and since then there have been issues with Copilot, Multi-Factor Authentication, SharePoint, and OneDrive.

In July 2024, a distributed-denial-of-service attack caused global issues with Azure cloud service. However, none of these come anywhere close to the scale of the CrowdStrike incident that same month, which disabled about 8.5 million Windows devices worldwide and caused huge disruption to emergency services, airports, law enforcement, and other critical organisations.

Slack’s recent outage

Microsoft 365 services were also not the only ones facing problems this week. On Feb. 26, Slack experienced a significant outage, disrupting services like messaging and workflows for thousands of users worldwide. This was caused by maintenance action in a database system which led to an “overload of heavy traffic.”