A global tech outage was disrupting operations in multiple industries on Friday, with airlines halting flights, some broadcasters off-air and everything from banking to health care hit by system problems.

According to an alert sent by global cybersecurity firm Crowdstrike to its clients and reviewed by Reuters, the company's Falcon Sensor software is causing Microsoft Windows to crash and display a blue screen, known informally as the "blue screen of death."

The company told NBC News that the outage is related to an issue in the most recent update, which is now being rolled back. The problem crashed Windows machines and servers, sending them into a loop of recovery so that they couldn't restart.

Earlier on Friday, the company told users, "CrowdStrike is aware of reports of crashes on Windows hosts related to the Falcon Sensor."

Major disruptions reported by airlines and airports grew.

In the U.S., the Federal Aviation Administration said the airlines United, American, Delta and Allegiant had all been grounded. Travellers at Los Angeles International Airport slept on a jetway floor, using backpacks and other luggage for pillows, due to a delayed United flight to Dulles International Airport early on Friday. Airlines, railways and television stations in the United Kingdom were being disrupted by the computer issues.

It was not immediately clear whether all reported outages were linked to Crowdstrike problems or there were other issues at play.

Some of the U.S. airline disruptions appear to have been affected by issues with Microsoft software. Microsoft said an outage started at about 6 p.m. ET on Thursday, with a subset of its customers experiencing issues with multiple Azure services in the Central U.S. region.

A spokesperson from Toronto's Pearson Airport told CBC News the impacts varied "airline to airline."

Azure is a cloud computing platform that provides services for building, deploying, and managing applications and services. Separately, Microsoft said it was investigating an issue impacting various Microsoft 365 apps and services.

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."

The website DownDectector, which tracks user-reported internet outages, recorded growing service disruptions at Visa, ADT security and Amazon that appear related to the Microsoft issues.

Several airports report delays

Airline traffic was especially affected, though the impacts were variable.

Edinburgh Airport said the system outage meant waiting times were longer than usual. London's Stansted Airport said some airline check-in services were being completed manually, but flights were still operating.

Widespread problems were reported at airports in India, affecting thousands. Hong Kong's Airport Authority said in a statement that the outage was affecting some airlines at the city's airport and they had switched to manual check-in.

Tokyo, Amsterdam, Berlin and several Spanish airports reporting problems with their systems and delays.

Zurich Airport, the busiest in Switzerland, suspended landings on Friday morning but said flights headed there that were already in the air were still allowed to land. It said that several airlines, handling agents and other companies at the airport were affected, and that check-in had to be done manually in some cases, but that the airport's own systems were running.

Some TV and radio broadcasters off-air

News outlets in Australia reported that airlines, telecommunications providers and banks, and media broadcasters were disrupted as they lost access to computer systems. 

The CBC has experienced some issues with automated broadcasting processes, affecting control room operations, cameras and graphics.

No evidence of cybersecurity issue: Australian government

There was no information to suggest the outage was a cybersecurity incident, the office of Australia's National Cyber Security Co-ordinator Michelle McGuinness said in a post on X.

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." The company did not respond to a request for comment. It did not explain the cause of the outage further.

Australia appeared to be severely affected by the issue. Outages reported on the site DownDetector included the banks NAB, Commonwealth and Bendigo, and the airlines Virgin Australia and Qantas, as well as internet and phone providers such as Telstra.

Britain's National Health Service (NHS) said a global IT outage was affecting its appointment and patient record system, but that it hadn't seen any impact on critical emergency services.