A raft of global institutions - including major banks, media outlets and airlines - have reported suffering a mass IT outage.
The US state of Alaska has warned its emergency services are affected, while several of the country's airlines have grounded their flights around the globe.
Australia - which has been particularly hard hit - has seen broadcast networks scrambling on air as systems failed and supermarkets crippled. Sky News UK went completely off air as a result of the issues.
The cause of the outage is unclear, but many of those impacted have linked it to Microsoft PC operating systems.
An official Microsoft 365 service update posted to X earlier in the day said " we're investigating an issue impacting users ability to access various Microsoft 365 apps and services".
However, a Microsoft spokesperson told the OceanNewsUK on Friday that "the majority of services were recovered" hours earlier.
A spokesperson for Australia's Home Affairs Minister said the outage appears to be related to an issue at global cybersecurity firm Crowdstrike, and the country's cybersecurity watchdog said there is no information to suggest it an attack.
“Our current information is this outage relates to a technical issue with a third-party software platform employed by affected companies," they said in a statement.
Alaskan officials said many 911 and non-emergency call centres are not working properly.
United, Delta and American Airlines - which are all based in the United States - have issued a "global ground stop" on all of their flights. And in Australia, carriers Virgin Australia and Jetstar have also had to delay or cancel flights.
Australian telecom firm Telstra has said triple-0 call centres - the main emergency contact in the country - are not affected, but that it is working with other state emergency services providers to implement backup processes.
Social media users have reported queues at Australian stores like Woolworths, with payment systems downed, and trouble accessing financial institutions like the National Australia Bank.
