A mass IT outage has caused chaos around the world, with major airlines among the victims.
A mass IT outage has caused travel chaos around the world, with banking and healthcare services also badly hit.
Many flights have been grounded, with queues and delays at airports.
Cyber-security firm Crowdstrike has admitted that the problem was caused by an update to its Falcon antivirus software, designed to protect Microsoft Windows devices from malicious attacks.
Microsoft has said it is taking “mitigation action” to deal with “the lingering impact” of the outage.
Here is a summary of what else we know so far.What caused the IT outage?
The boss of global cyber-security firm Crowdstrike, George Kurtz, says the problems were caused by a “defect” in a “content update” for Microsoft Windows devices.
He added: “The issue has been identified, isolated and a fix has been deployed.”
Mr Kurtz said the issues did not affect other operating systems, adding: “This is not a security incident or cyber-attack.”
His statement followed widespread reports that Crowdstrike, which produces antivirus software, had issued a software update that caused Windows devices to crash.
