Microsoft Outlook Down for Hours After Network Upgrade Shuts Servers

Microsoft Outlook email and other Microsoft services were down for hours starting Thursday, and Microsoft has said a recent upgrade to its network shut down some servers and caused the outage, The New York Times reported. By Friday morning the company said its systems were steadily improving and that it had brought services back in stages.

The Times described it as a global outage. Hospitals, schools, businesses and Congressional offices in Washington lost access to email, and even Microsoft’s own staff could not use it.

What Microsoft says caused the outage

Microsoft traced the problem to its own network upgrade, which took some servers offline. The company had apologized at least twice by Friday morning, according to the Times. Microsoft has not said the outage involved any attack or outside interference.

In a statement, Microsoft said it chose a slow recovery on purpose. “We restored services gradually, validating stability at each stage,” the company said, adding that the approach took longer but helped make sure the restoration held.

How engineers brought email back

Late into Thursday night, hundreds of Microsoft engineers and top executives joined a video conference from darkened offices and home basements to work through the failure, the Times reported. Scott Guthrie, the most senior executive in charge of the company’s computing infrastructure, was proposing fixes on the call, according to a person familiar with it who was not authorized to speak publicly.

A large part of the discussion was about switching other services off for a while. The worry was a “stampeding herd”: when systems come back online, a flood of users and pending requests can overload them and knock them offline again. Bringing services back step by step was meant to prevent that, and according to the Times the approach worked.

Is Outlook working again?

As of Friday morning, Microsoft said its systems were steadily improving. It has not given an exact time when every affected service was fully restored. Microsoft also has not disclosed how many users or which regions beyond those named were affected.

Anyone who still cannot send or receive mail can check Microsoft’s official service status page first. Signing out of Outlook and back in, or updating the app, are other simple checks to try.

Why it matters

Much of the world’s email runs through Microsoft Outlook, so an outage there reaches far beyond one company. The Times called the incident the latest reminder that the technology behind daily life and business depends on a small number of big providers.

The cause also matters. Outages are often blamed on cyberattacks, but this one came from a change Microsoft made to its own systems. The Times noted that large companies can introduce serious flaws while updating or maintaining their global networks, and that hospitals, law enforcement, government agencies and other essential services can be left unable to work for hours or days when that happens.

For the hospitals, schools and offices hit on Thursday, the outage meant hours without email until Microsoft’s staged recovery reached them.

Source: The New York Times