TAIPEI (Taiwan News) — Major airlines affected by a global Microsoft outage have gradually resumed normal operations at Taiwan’s main international airport, the Taoyuan International Airport Company said on Saturday (July 20).

The airport said the incident caused Delta and United airlines to make changes to some flights to or from the airport on Saturday, per CNA. It advised passengers to check with airline companies to confirm their itineraries.

The outage, which affected airlines worldwide, caused some airlines operating out of Taoyuan International to use manual processes for check in and seat allocation on Friday. The airport said HK Express, Asia Air, Jeju Air, and Jetstar were among the airlines affected.

The outage also affected National Taiwan University Hospital, though staff said systems were restored within 30 minutes. There have also been reports from across the world of the outage affecting emergency services, banks, international border crossings, factories, retailers, and others.

The outage affected Microsoft Windows users, and began after major cybersecurity firm CrowdStrike issued an update, per AP. On Saturday, CrowdStrike said the outage was not a result of hacking, apologized, and said a fix was on the way.