Photos: Airlines resume services after global IT crash caused by Microsoft-CrowdStrike issue wreaks havoc

Paris: Airlines were gradually coming back online Saturday after global carriers, banks and financial institutions were thrown into turmoil by one of the biggest IT crashes in recent years, caused by an update to an antivirus program.

Passenger crowds had swelled at airports on Friday to wait for news as dozens of flights were cancelled and operators struggled to keep services on track, after an update to a program operating on Microsoft Windows crashed systems worldwide.

Multiple US airlines and airports across Asia said they were now resuming operations, with check-in services restored in Hong Kong, South Korea and Thailand, and mostly back to normal in India, Indonesia and at Singapore's Changi Airport (above) as of Saturday afternoon.

Microsoft said the issue began at 1900 GMT on Thursday, affecting Windows users running the CrowdStrike Falcon cybersecurity software. CrowdStrike said it had rolled out a fix for the problem and that it could take a few days for things to return to normal.

A text message alert from a British NHS Doctor's surgery on the Wirral. Reports from the Netherlands and Britain suggested health services might have been affected by the disruption, meaning the full impact might not yet be known.

Media companies were also hit, with Britain's Sky News saying the glitch had ended its Friday morning news broadcasts, and Australia's ABC similarly reporting major difficulties.

Sydney domestic airport. By Saturday, services in Australia had mostly returned to normal, but Sydney Airport was still reporting flight delays.

Adolfo Suarez Madrid–Barajas Airport in Madrid. Australian authorities warned of an increase in scam and phishing attempts following the outage, including people offering to help reboot computers and asking for personal information or credit card details.

Hong Kong International Airport. While some airports halted all flights, in others airline staff resorted to manual check-ins for passengers, leading to long lines and frustrated travellers.

The US Federal Aviation Administration (FAA) initially ordered all flights grounded "regardless of destination", though airlines later said they were re-establishing their services and working through the backlog.

A passenger told AFP that the situation was returning to normal at Delhi Airport by midnight on Saturday with only slight delays in international flights.

Ninoy Aquino International airport in Manila. Low-cost carrier AirAsia said it was still trying to get back online, and had been "working around the clock towards recovering its departure control systems (DCS)" after the global outage. It recommended passengers arrive early at airports and be ready for "manual check-in" at airline counters.

BER Berlin-Brandenburg Airport in Schoenefeld, Germany. Chinese state media said Beijing's airports had not been affected. In Europe, major airports including Berlin's Brandenburg Airport (above), which had suspended all flights earlier on Friday, said departures and arrivals were resuming.

Companies were left patching up their systems and trying to assess the damage, even as officials tried to tamp down panic by ruling out foul play.