Microsoft Probes Cause of Global Web Outage

Microsoft technicians today continued to search for the cause of a massive outage that disrupted user access to Office 365, Skype, Xbox Live and other online services, in some cases for more than 16 hours.

The outage, which affected large swaths of the U.S. and Europe, was the second this month of Microsoft’s online services, though a disruption on March 7 only lasted about an hour.

This week’s disruption began Tuesday, about 1:15 p.m. U.S. Eastern Time, and was declared resolved at 5:50 a.m. ET.

“We’ve monitored the infrastructure and have confirmed that restarting the affected systems remediated impact,” Microsoft said on the Office 365 status page. 

The longest-running disruption involved the Office 365 OneDrive file-hosting service.

“In some cases, after signing in to OneDrive, users were unable to access their content,” that status report said. “As the issue was intermittent in nature, users may have been able to reload the page or make another attempt successfully.”

An initial attempt to restore OneDrive was unsuccessful.

“We’ve determined that the previously resolved issue had some residual impact to the service configuration for OneDrive,” Microsoft said in a status update Tuesday afternoon. “We’re performing an analysis of the affected systems to determine what further steps are needed for full recovery.”

At the height of the outage, those affected were unable to access Outlook email. 

“Users may be intermittently unable to sign in to the service,” that advisory said. “As the issue is intermittent in nature, users may be able to reload the page or make another attempt successfully.”

It’s unclear precisely how or if the outage was connected to a disruption Tuesday of Microsoft’s Azure cloud, during the same time.   

“Between 17:30 and 18:55 UTC on 21 Mar 2017, a subset of Azure customers may have experienced intermittent login failures while authenticating with their Microsoft Accounts,” reads the advisory on the Azure status page.

“This would have impacted the ability for customers to authenticate to their Azure management portal (https://portal.azure.com), PowerShell, or other workflows requiring Microsoft Account authentication,” it continued. “Customers authenticating with Azure Active Directory or organizational accounts were unaffected.” 

Microsoft deployed a patch to end the 85-minute outage and work continued today to figure out exactly what happened.

“Engineers will continue to investigate to establish the full root cause and prevent future occurrences,” Microsoft said.

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