The CrowdStrike outage affected less than 1% of Windows machines, but it was enough to send the world into chaos

• A worldwide IT outage caused by a CrowdStrike update disrupted air travel, banking, and TV.
• Microsoft estimated that 8.5 million machines using Windows software were affected.

A worldwide IT outage on Friday caused by an update issued by cybersecurity firm CrowdStrike resulted in widespread disruptions to air travel, banking services, and even television broadcasts.

Microsoft announced Saturday that the outage affected less than 1% — or about 8.5 million — machines using Windows software worldwide.

In a blog post, Microsoft said the outage's effect on businesses worldwide reflected "the use of CrowdStrike by enterprises that run many critical services."

Business Insider previously reported that the massive outage also reflects Microsoft's and CrowdStrike's market dominance. Data from Statista shows that Windows had about 72% of the global market share of operating systems as of February, while one estimate shows CrowdStrike's market share in the "endpoint protection" security category at nearly 24%.

"This incident demonstrates the interconnected nature of our broad ecosystem — global cloud providers, software platforms, security vendors and other software vendors, and customers," Microsoft wrote. "It's also a reminder of how important it is for all of us across the tech ecosystem to prioritize operating with safe deployment and disaster recovery using the mechanisms that exist."

On Friday, CrowdStrike released a faulty system update, resulting in the most widespread tech outages in history. The update specifically affected Windows software, while machines running Mac and Linux were left unaffected, CrowdStrike announced.

The ensuing chaos resulted in airlines and hotels using pen and paper to take people's information in and the cancellation of medical services at some European hospitals. Photos from airports and stores showed blue error screens on computers and flight information displays.

On Friday, CrowdStrike CEO George Kurtz said the issue had been "identified, isolated, and a fix has been deployed." This fix includes manually deleting the file update on affected computers.

Although the fix appears simple, experts told Business Insider it could take companies with fewer IT personnel weeks to resolve the "blue screen of death" on every device, meaning some industries could feel effects for a while.

Andrew Peck, a cybersecurity expert at Loughborough University in the UK, told CNN that fixing the issue across multiple companies worldwide could cost billions.

CrowdStrike and Microsoft did not immediately respond to a request for comment.