Cause of widespread outage impacting Microsoft users identified

“CrowdStrike is actively working with customers impacted by a defect found in a single content update for Windows hosts,” said a Friday morning message from CrowdStrike CEO George Kurtz on X. Reports said the outage grounded flights, impacted banks and more.

Around 10 hours earlier , the Microsoft 365 Status page on X posted that the company was investigating an issue impacting users of Microsoft 365 apps. Over the next several hours, it reported that traffic was being re-routed.

So, what happened?

Kurtz said the issue wasn’t a cyberattack.

“Mac and Linux hosts are not impacted. This is not a security incident or cyberattack. The issue has been identified, isolated and a fix has been deployed,” he said. “We refer customers to the support portal for the latest updates and will continue to provide complete and continuous updates on our website.”

Even so, the outage had a considerable impact on banks, airports, TV stations, hotels, and countless other businesses are all facing widespread IT outages, according to WIRED . The outlet said it left flights grounded and resulted in “widespread disruption.”

Worldwide, many Windows users were faced with what is known as Blue Screens of Death (BSODs). WIRED reported that the outage was linked to a software update from CrowdStrike, a cybersecurity firm. Officials cited by the outlet said CrowdStrike pushed a misconfigured/corrupted update out to its customers.

Microsoft described it as “a configuration change in a portion of our Azure backend workloads, caused interruption between storage and compute resources which resulted in connectivity failures that affected downstream Microsoft 365 services dependent on these connections.”

As of approximately 6:30 a.m. ET, the Microsoft 365 Admin Center still had a Service Degradation alert on its website. It said users might be unable to access certain apps and services.

“Users may notice that some of the affected users are seeing relief as we continue to mitigate the impact,” said page offering updates on the outage .

While it said the underlying cause of the issue had been fixed, it also said the residual impact was still affecting some Microsoft 365 apps and services. Microsoft said it was treating the event as a high priority.

“We further recommend organizations ensure they’re communicating with CrowdStrike representatives through official channels. Our team is fully mobilized to ensure the security and stability of CrowdStrike customers,” said Kurtz.