A mass IT outage has affected business, airlines, banks and hospitals around the world.
The outage, which spread widely on Friday morning, is believed to be related to Microsoft and global cybersecurity firm CrowdStrike.
However, it is unknown if it is the same problem affecting airports and train services across the globe.
Follow live: Major services across the world affected by outage
CrowdStrike’s CEO said a “defect” was found in “a single content update for Windows hosts,” and a “fix has been deployed”.
Microsoft also said a resolution for Windows devices affected by the outage is “forthcoming”.
Here is a rundown of how the outage spread, and what we know about it so far…
Crowdstrike CEO points to ‘defect’
At 10.45am on Friday, the head of CrowdStrike issued a statement to say a “defect” was found in “a single content update for Windows hosts”.
George Kurtz added “this is not a security incident or cyberattack” and said the “issue has been identified, isolated and a fix has been deployed”.
Issues still persist however, and customers said the problems came after an update to the code of its Falcon Sensor software.
The agent “blocks attacks on your systems while capturing and recording activity as it happens to detect threats fast”, according to the cyber security firm’s website.
Users reported that their Windows PC’s crashed to the “blue screen of death” after the software update.
First reports from Australia
The first reports of IT issues came overnight from Australia, when a spokesperson for the country’s home affairs minister said the outage appeared to be related to an issue at CrowdStrike.
The countries National Cyber Security Coordinator described it as a “large-scale technical outage,” but said there was no indication it was a cyber attack.
Australian firms were also the first to report a variety of issues: Chain store Woolworths said its payment systems went down, while the National Australia Bank was also affected.
Flight carriers Virgin Australia and Jetstar were forced to delay or cancel flights when departure screens went blank at Sydney Airport.
Outages spread across globe
A spike in outages was then recorded across a number of websites and services just before 6am in the UK, according to the internet tracking website Downdetector.
NHS England said in a statement at 10.20am the outage was “causing disruption in the majority of GP practices” as bookings could not be recorded using the service’s EMIS computer system.
They added there was no known impact on 999 calls or emergency services.
Airlines and airports in the UK, US, India and elsewhere also faced severe delays over the issue: Ryanair advised passengers to arrive for their flights at least three hours early over the disruption, while Edinburgh Airport said the outage meant waiting times were longer than usual.
Major US airlines including American Airlines, Delta Airlines and United Airlines were grounded, while airports in Germany, Amsterdam and Spain reported issues.
Major train operators TransPennine Express and Govia Thameslink Railway – which operates the Southern, Thameslink, Gatwick Express and Great Northern brands – were also disrupted in the UK, and people at the Port of Dover were told to expect longer waiting times.