Services from airlines to healthcare, shipping and finance were coming back online Friday after a mistake in a security software update sparked hours-long global computer systems outages, another incident highlighting the vulnerability of the world’s interconnected technologies.

After the outage was resolved, companies were dealing with backlogs of delayed and canceled flights and medical appointments, missed orders and other issues that could take days to resolve. Businesses also face questions about how to avoid future blackouts triggered by technology meant to safeguard their systems.

A software update by global cybersecurity firm CrowdStrike, one of the largest operators in the industry, triggered systems problems that grounded flights, forced broadcasters off air and left customers without access to services such as healthcare or banking. Global shipper FedEx faced major disruptions and some moderators who police content on Meta’s Facebook were hit.

CrowdStrike is not a household name but it is an $83 billion company with more than 20,000 subscribers around the world including Amazon.com and Microsoft. CrowdStrike CEO George Kurtz said on social media platform X that a defect was found “in a single content update for Windows hosts” that affected Microsoft customers.

“We’re deeply sorry for the impact that we’ve caused to customers, to travelers, to anyone affected by this, including our company,” Kurtz told NBC News.

CrowdStrike has one of the largest shares of the highly competitive cybersecurity market, leading some industry analysts to question whether control over such operationally critical software should remain with just a handful of companies.

The outage also raised concerns that many organizations are not well prepared to implement contingency plans when a single point of failure such as an IT system, or a piece of software within it, goes down. But these outages will happen 추천 again, experts say, until more contingencies are built into networks and organizations introduce better back-ups.

CrowdStrike shares closed down 11%. Its rivals SentinelOne shares closed up 8 percent and Palo Alto Networks closed up 2 percent. Microsoft closed down 0.7 percent.

The scale of the outage was massive, but not yet quantifiable because it involved only systems that were running CrowdStrike software, said Ann Johnson, who heads Microsoft’s security and compliance business.

“We have hundreds of engineers right now working directly with CrowdStrike to get customers back online,” she said.