Microsoft has revealed that around 8.5 million computers globally ground to a halt, as a security program glitch crashed about one per cent of all Windows operating systems and the infrastructure it controls.

At 2:09pm (AEST) on Friday, Crowdstrike released a routine update to its cybersecurity program, Falcon, for Windows systems 7.11 and above

This happens multiple times a day, but this update contained a piece of bad code, and triggered a system crash, sending devices around the world spiralling into the ‘Blue Screen of Death’.

Microsoft said “While software updates may occasionally cause disturbances, significant incidents like the CrowdStrike event are infrequent.”

Flights were grounded, hospitals were affected, and some banks, shops and businesses couldn’t trade… and broadcasters were forced to awkwardly fill airtime.

CrowdStrike released a fix within hours, but days later some things are still out.

The cybersecurity company warned it could take time to restore some systems that need to manually weed out the flawed code.

It is estimated the IT outage could have cost Australians billions of dollars.

There are also warnings the digital debacle is fertile ground for opportunistic scammers, looting in the aftermath of the CrowdStrike chaos.