Why is the internet down worldwide? Everything you need to know

A massive IT outage has knocked out Windows computers around the world. Photo / 123RF

A massive IT outage has knocked out Windows computers around the world, taking websites, airports and banks offline as engineers scramble to reboot their systems.

The problem began tonight as workers found their PCs crashing, showing the so-called “blue screen of death” and entering recovery mode.

While companies across the globe struggle to get online, here is what we know so far about the problem.

What has happened and why is Windows down?

Hundreds of thousands of computers around the world have suddenly shut down, impacting businesses, transport links and TV broadcasts globally.

A software problem with a piece of cyber-security technology called CrowdStrike appears to be to blame. The specific piece of technology, CrowdStrike Falcon Sensor, is used to protect against hacking threats, but engineers were quick to blame a problem with the system for causing the massive outage.

The issue mostly seems to be affecting PCs running on Microsoft’s Windows 10 software.

Who has been affected?

An awful lot of people. While we still do not know the full impact of the bug, so far today we have seen TV stations, transport links and banks complaining of problems.

Sky News was forced to pull its morning breakfast show in Britain and replace it with pre-recorded footage. Ryanair has warned on its website to expect major delays at airports around the world.

Images on social media showed computers across airports and transport hubs displaying the notorious “blue screen of death”. Users also reported being stuck on planes on the runway.

Britain’s Gatwick Express warned commuters to expect short-notice cancellations across the train network.

Is it a cyber attack?

So far, all indications point to a software problem with CrowdStrike, but we know little about its root cause.

The technology is designed to protect computers against cyber incidents. As of 8pm, CrowdStrike had issued no public update on the origin of the problem.

However, on a Reddit forum used by CrowdStrike engineers and cyber experts, users pointed to an update to customers which said: “CrowdStrike is aware of reports of crashes on Windows hosts related to the Falcon Sensor. Symptoms include hosts experiencing a bugcheck\blue screen error related to the Falcon Sensor.”

What is CrowdStrike and who owns it?

CrowdStrike is one of the world’s largest cyber-security technology companies – valued at over US$80 billion ($132b) – whose tools are used by businesses around the planet.

Its typical technology is known as endpoint detection and response – a type of antivirus – used to deal with hacking threats.

These products are updated regularly to deal with potential new cyber threats and often automatically add new tools to your PC.

Troy Hunt, a cyber security expert, added in a post on X, formerly known as Twitter, that CrowdStrike’s tools often have “privileged” access on PCs, meaning they have broad control over the machines to try to remove threats.

However, he added that “also means that if something goes wrong with an update, it’s able to catastrophically nuke your machine”.

CrowdStrike the business is publicly listed in New York and owned by technology investors and major funds such as Blackrock.

Why was Sky News down?

Sky News viewers in Britain might have been expecting the morning’s breakfast show.

But when people tuned in this morning, the typical broadcast was replaced with the error message: “We apologise for the interruption to this broadcast. We hope to restore the transmission of Sky News shortly.”

Presenter Jacquie Beltao said on Twitter: “We’re obviously not on air – we’re trying.”

Sky’s typical broadcast was replaced by a string of archive videos and pre-recorded news reports. The issue also hit other broadcasters around the world, including Sky’s international divisions, as well as ABC.