A massive global technology outage on Friday caused chaos, grounding flights, disrupting health services, crashing payment systems, and blocking access to Microsoft services. Experts are calling it one of the largest IT failures in history.

The disruption was traced back to a cybersecurity firm named CrowdStrike, whose software update malfunctioned, impacting computers running Windows worldwide. Here’s what we know about the incident and the company behind it.

What is CrowdStrike?

Founded in 2011 and based in Austin, Texas, CrowdStrike has rapidly grown into a leading cybersecurity firm. It offers a range of cloud-based security services and has received substantial funding from major Silicon Valley investors, including Google’s venture capital arm. With thousands of employees, CrowdStrike serves businesses across the globe and boasts that it protects 538 out of the Fortune 1000 companies. By Thursday, the company had a market value of around $83 billion, but its stock price plummeted by as much as 13% following Friday’s outage.

CrowdStrike is renowned for its ability to fend off hackers and malware, but it has also been involved in high-profile cyber investigations. The Democratic National Committee (DNC) enlisted CrowdStrike to investigate the 2016 Russian hack of its servers, and Sony Pictures hired the firm to examine a 2014 cyberattack linked to North Korea.

CrowdStrike’s role in the DNC investigation also had political ramifications, notably during the first impeachment of Donald Trump. Trump controversially suggested the Ukrainian president investigate CrowdStrike, echoing a debunked conspiracy theory related to the DNC hack.

How Did CrowdStrike Cause the Global Outage?

The global outage was triggered by an update to CrowdStrike’s flagship cybersecurity platform, Falcon. This update malfunctioned, disrupting systems and software, including Microsoft’s Windows products, around the world.

Ironically, the software meant to prevent crashes and disruptions ended up causing them. CrowdStrike’s CEO, George Kurtz, apologised for the outage, attributing it to a faulty piece of code.

“This is not a security incident or cyberattack. The issue has been identified, isolated, and a fix has been deployed,” Kurtz stated on Twitter. “We refer customers to the support portal for the latest updates and will continue to provide complete and continuous updates on our website.”

Adding to the chaos, Microsoft’s Azure cloud services also experienced an outage on Friday, though Microsoft clarified that this was unrelated to CrowdStrike’s issues and that Azure services were back online.

What’s the temporary fix?

It’s important to note that personal devices like home computers or smartphones are generally not affected by this type of outage; the disruption primarily impacts businesses.

Microsoft is advising clients to try a simple but sometimes effective troubleshooting step: rebooting the system. In some cases, this may need to be done up to 15 times. The tech giant reported that this method has been particularly effective for users of virtual machines, where the computer and screen are separate.

“Several reboots (up to 15 in some reports) may be necessary, but overall feedback indicates that reboots are a valuable troubleshooting step at this stage,” Microsoft stated.

For those with advanced computing knowledge, Microsoft suggests deleting a specific file— a solution that has also been recommended by a CrowdStrike employee on social media. However, this fix is intended for experts and IT professionals, not for the average user.