A widespread technology outage affected companies and services across industries Friday — grounding flights, knocking banks and hospital systems offline and affecting other organizations in Pittsburgh and around the world.

At the heart of the massive disruption is CrowdStrike, a cybersecurity firm that provides software to scores of companies worldwide. The company says the problem occurred when it deployed a faulty update to computers running Microsoft Windows, noting that the issue behind the outage was not a security incident or cyberattack.

CrowdStrike has said a fix is on the way. Still, chaos deepened hours after the problem was first detected.

The disruptions began when a faulty update was pushed out from CrowdStrike for one of its tools, “Falcon.”

In a statement about the ongoing situation, the company said the defect was found “in a single content update for Windows hosts” — noting that Mac and Linux systems were not impacted.

But, because scores of companies rely on CrowdStrike for their security needs with Windows as their operating system, the consequences of this kind of technical problem have been far-reaching. As a result, affected computer after computer showed the “blue screen of death” error message.

By Friday afternoon, nearly all airlines restored their systems at the Pittsburgh International Airport but it delayed flights and created massive lines.

The Federal Aviation Administration said United Airlines, American Airlines, Delta Air Lines and Allegiant Airlines flights were grounded.

The airport posted on its social media accounts Friday morning that some airlines were having delays because of the IT issues affecting airlines, banks, media outlets and other companies around the world. The post said airport systems and security checkpoints were not affected by the outage.

A majority of Pittsburgh’s airlines were up and running again, according to Bob Kerlik, spokesperson for the Allegheny County Airport Authority.

There could still be some residual delays or cancellations as airlines adjust their schedules, Kerlik said. He recommended that travelers continue to check the status of their flights

The issue affected Microsoft 365 apps and services, and escalating disruptions continued hours after the technology company said it was gradually fixing it.

According to FlightAware, as of 4 p.m. Friday, there were nearly 8,400 total delays within, into or out of the U.S. today, with around 2,500 total cancellations.

Despite obvious frustration, most travelers remained calm and respectful in the midst of delays and cancellations.

“Honestly, I’m really impressed by how everybody is just calm,” said Carissa Hillman, who has been in Pittsburgh from Michigan for a three-day work conference. “There’s no sense in being angry or yelling. I haven’t seen any of that. You want to be safe when you’re flying, so you don’t want to fly when there’s a cyber issue.”

Microsoft 365 posted on X that the company was “working on rerouting the impacted traffic to alternate systems to alleviate impact in a more expedient fashion” and that they were “observing a positive trend in service availability.”

Other impacts

The Arnold Palmer Regional Airport in Unity canceled a flight to Orlando — one of its two Friday flights — because of the outage, which impacted its carrier Spirit Airlines, said Executive Director Gabe Monzo.

The airport’s flight to Myrtle Beach took off later than departure time, he said.

The outage didn’t just affect airports.

The Allegheny County parks department, jail, medical examiner’s office and courts were on limited operation, according to a statement.

The parks department only accepted cash payments at some golf courses and pools. The jail canceled visitations and some of the court’s record functions — like passport photos and marriage licenses — weren’t available.

The Pittsburgh Zoo & Aquarium was cash-only for admission Friday.

The zoo’s retail and concessions were able to receive card payments, said spokesperson Alex Cauley.

Less than 10% of UPMC’s Microsoft Windows-based devices were affected by the outage, according to a health system spokesperson.

“UPMC’s IT team intervened early to mitigate the problem and is restoring servers and PCs,” the spokesperson said in a statement. “Patient care has not been affected and our facilities are operational. Our emergency departments are open and appointments and procedures will proceed as scheduled.”

The Independence Health System wasn’t impacted by the outage, said spokesperson Robin Jennings.

Giant Eagle supermarkets and GetGo locations were open as usual, but some pharmacies were delayed in filling prescriptions, according to spokesperson Jannah Jablonowski.

The Pennsylvania Lottery’s Keno and virtual sports games were not available Friday morning because of the outage, which is impacting some of the company’s servers, said spokesperson Ewa Swope. But the games were back online at 11 a.m.

Rivers Casino Pittsburgh on the North Shore and Live Casino Pittsburgh in Hempfield were not affected by the outages, but the Starbucks located in Rivers Casino was only accepting cash Friday, according to spokesperson Jack Horner.

Experts stress that Friday’s disruptions underscore the vulnerability of worldwide dependence on software that comes from only a handful of providers.

“It is an ‘all our eggs are in one basket’ situation,” Craig Shue, professor and computer science department head at Worcester Polytechnic Institute, said in emailed commentary. “This lets us make sure our ‘basket’ is high quality: the software provider tries to identify threats and respond to them quickly. But at the same time, if anything goes wrong and the basket fails, we have a lot of broken eggs.”

The Associated Press contributed to this report.