Microsoft Outlook Down Still? Microsoft Restores Email After Global Outage of Over 24 Hours

Microsoft said early Saturday it had restored Outlook and other Microsoft 365 services. The outage lasted more than 24 hours and cut off email for businesses, governments and households around the world.

"We have completed our efforts to address the underlying issue of the incident and restored service to the remaining impacted customers and regions," the company said in a post on X.

The company also apologized and gave its first detailed explanation of what went wrong. It blamed a problem introduced during an earlier upgrade to its network capacity.

Apology and explanation

In a statement Friday, Microsoft said it was "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," the company said.

Microsoft said the outage was "a technical issue not related to cyber or AI / agents." It said the incident "was introduced by an issue during an earlier network capacity upgrade" that "surfaced following a recent network change."

The company defended the slow pace of recovery. "Given the scale of demand, we restored services gradually, validating stability at each stage," it said. "While this took longer, it helped ensure a stable restoration."

Microsoft said it "will provide a full post-incident report once our review is complete." It has not said when that report will be released.

Overloaded servers

Microsoft's earlier updates described a chain reaction inside its email infrastructure.

On Thursday night, the company said a process on the affected servers responsible for establishing secure connections had become overwhelmed, causing the servers to stop processing requests. As servers failed, traffic shifted to others, which then became overloaded. Servers that came back online were swamped by reconnection traffic and failed again.

Engineers tried several fixes, including patches to authentication and routing components, before services began to stabilize Friday.

By about 9:17 a.m. ET Friday, Microsoft said email queues were "significantly reduced and approaching normal levels." Later updates reported sustained recovery across the affected environments.

What Outlook users lost

Outlook, Microsoft's email and calendar application for Windows, Mac, the web and mobile devices, was the product hit hardest.

Starting Thursday afternoon, many users could not open their mailboxes. Others could not send or receive email, and calendar invitations and meeting scheduling failed. The disruption spread to Teams, the Copilot AI assistant and other Microsoft 365 services that rely on Exchange Online, the company's cloud email system.

Outlook problem reports on outage tracker Downdetector peaked at more than 130,000 in the United States shortly after 1 p.m. ET Thursday. Reports came in from more than 70 countries and territories.

To limit the damage, Microsoft extended its incoming email timeout window to 48 hours, so messages delayed during the outage would be delivered rather than bounced back to senders.

Global disruption

The outage hit organizations across continents.

Japanese government ministries went back to paper after being unable to send email for most of Friday's workday. Australia's spy agency and federal police were affected, and courts and schools there opened to unusable inboxes. Staff at major banks in Hong Kong were locked out of email and Teams. U.S. city governments, including Miami Beach and Austin, asked residents to phone instead of emailing.

Banks including Standard Chartered and ING Australia warned customers about scammers posing as technical support during the disruption.

Some users may still see problems

Although Microsoft says service has been restored, it warned that some users may still experience intermittent access issues as systems settle and backlogs clear.

Users still having trouble are advised to:

• Restart Outlook on desktop and mobile so the app can reconnect to Microsoft's servers.
• Check for delayed messages, since email sent during the outage may arrive late as queues clear.
• Resend important messages if senders received bounce-back notices.
• Check official channels, including Microsoft's service status pages and its Microsoft 365 Status account on X.
• Be wary of scams, and ignore unsolicited calls or messages offering to fix Microsoft accounts.

IT administrators can follow the incident through the service health dashboard in the Microsoft 365 admin center.

Compensation questions

The length of the outage has raised questions about compensation for business customers.

Microsoft's service level agreements for business products such as Exchange Online offer partial credits when uptime falls below certain levels. Credits are not automatic, and customers generally must file a claim through the Microsoft 365 admin center. Consumer users of Outlook.com are not typically eligible.

A troubled year

The incident is the latest in a series of Microsoft 365 failures in 2026. In January, the service was down across North America for almost 10 hours. In July, a faulty network configuration change caused about five hours of disruption. In late August, a faulty authentication configuration triggered problems that stretched over roughly three days.

The repeated outages have renewed questions about how much risk organizations take on by relying so heavily on a single cloud provider for email, meetings and documents.

Microsoft's upcoming post-incident report is expected to give more detail on how the network upgrade led to one of the company's most disruptive outages in years.