It is a massive computer outage affecting all corners of the globe. Which could well be the biggest outage the world has seen. Not a cyber attack, but a software update gone bad affecting Microsoft Windows computers using CrowdStrike cyber security software. Crowdstrike is aware of reports of crashes on Windows 4. Among the first, effected global airlines, their screen suddenly showing the so-called Blue Screen of death. From Thailand to Portugal, Spain to Scotland. And I think it's fair to describe this as organized chaos at the moment. Us Airlines went offline overnight, unable to process thousands of passengers. Every 15 minutes, we kept getting these text messages. Your flight is delayed a half hour, your flight is delayed an hour, your flight is delayed two hours. Major airlines grounded flights with Flight Radar 24 showing US airspace thinning out as endless lines wound through airport terminals. We received no... No, you can't get through to the airline. I don't think it's even in their hands. Mbc's Guadalajara in Atlanta. Passengers here reporting waits of up to four hours waiting on a line that stretched to the end of the terminal. By late today, 9,500 delays in the US, 2,700 cancelations, akin to the impact from a big winter storm.

We're deeply sorry for the impact that we've caused to customers. The CEO of CrowdStrike, which pushed the software update, appeared on today. We know what the issue is. We're resolving and have resolved the issue. But it wasn't just airlines and airports. Hospitals were also knocked offline. Nurses switching to paper orders. We can't scan the medicine to make sure you're not allergic to it. We can't scan the medicine to make sure that it's even yours. Many hospitals forced to cancel procedures. Allison Balo's father was supposed to have open heart surgery. They called and said that due to a global IT outage, they had to reschedule the surgery. Also, affected banks, 911 systems, trains, busses, and subways, retailers, FedEx and UPS, court systems, and driver's license offices. New York's governor trying to reassure the public. There is no risk to personal sensitive information that we're aware of. On X, Microsoft said it's working closely with CrowdStrike and across the industry to safely bring their systems back online. Doesn't this speak to a vulnerability that you have with Microsoft Windows that one line of code could break down the entire system? There's no vulnerability based on our knowledge.

What we understand right now is that the The outstrike update itself was flawed in how they access the system, and that is what has caused the global IT outage. All right, Tom, joining us now. Tom, how long is this outage expected to last? Well, the airlines seem to be back, mostly back, but the ripple effect from the flight cancelations could run well into the night, likely through the weekend. It could take hospitals, shipping companies, retailers, days or weeks to fully recover. Lester. Thanks for watching. Stay updated about breaking news and top stories on the NBC News app or follow us on social media.