Microsoft says 8.5M Windows devices were affected by CrowdStrike outage

Around 8.5 million devices — less than 1 percent of Windows machines globally — were affected by the recent CrowdStrike outage, according to a Microsoft blog post by David Weston, the company’s vice president of enterprise and OS security.

These are the first real numbers released by either Microsoft or CrowdStrike around the scale of yesterday’s outage, which was caused by an update to CrowdStrike’s cybersecurity software that led Windows machines to crash. (Mac and Linux devices were not affected.)

Although the number of affected devices was relatively low, the havoc was widespread and global, affecting banks, retailers, brokerage companies, rail networks, and more. Airlines halted flight operations around the world.

“While the percentage [of affected devices] was small, the broad economic and societal impacts reflect the use of CrowdStrike by enterprises that run many critical services,” Weston wrote.

He did not say what percentage of Windows devices with CrowdStrike software were affected. It’s also worth noting that even if only one computer crashed, it could potentially take down an entire network or data center.

Weston also wrote that “although this was not a Microsoft incident,” the company has been working with CrowdStrike to address the issue. Systems could be slow to recover if every affected computer requires a manual fix, but Weston said Microsoft and CrowdStrike have developed “a scalable solution that will help Microsoft’s Azure infrastructure accelerate a fix” and are also collaborating with Amazon Web Services and Google Cloud Platform.