Underlying issue causing global IT outage now fixed but some services still affected

The issue that caused a global IT outage affecting various businesses, including banks, airlines, and train companies, has been resolved.

Major U.S. airlines such as American Airlines (AAL), Delta Airlines (DAL), and United Airlines (UAL). have been grounded, while airports in Germany, Amsterdam, and Spain are also experiencing issues.

Reports early Friday suggested that the outage has affected devices running on Microsoft’s (NASDAQ:) Windows operating systems.

Microsoft later announced that the “underlying cause” of the issue has been fixed for its apps, but added that “residual impact” continues to disrupt some services.

Subsequent reports revealed that the issue had been caused by a content update released by CrowdStrike (NASDAQ:), a company providing cybersecurity solutions.

CrowdStrike CEO George Kurtz said the update has caused a “defect” for Windows hosts.

“Mac and Linux hosts are not impacted. This is not a security incident or cyberattack,” Kurtz said in a statement.

“The issue has been identified, isolated and a fix has been deployed,” he added.

“We refer customers to the support portal for the latest updates and will continue to provide complete and continuous updates on our website.

CRWD shares plunged more than 10% in premarket trading Friday.

The outage has affected several locations in Europe as well.

Ryanair, Europe’s largest airline by passenger numbers, warned customers of potential disruptions affecting “all airlines operating across the network,” though it did not specify the nature of these disruptions.

At Edinburgh Airport, passengers were unable to use automated boarding pass scanners, and monitors at security displayed a “server offline” message. The airport reverted to manual boarding pass checks, according to a Reuters witness.