Microsoft says services have been restored after a major network outage on Friday disrupted computer systems around the world.
The disruption affected a wide range of services. It struck airlines in Europe, Asia and the United States, hospitals in the Middle East, and a broadcaster in Britain.
The Wall Street Journal reported that more than 4,600 flights had been canceled and about 41,000 others delayed worldwide as of Friday evening.
The system glitch was reportedly caused by a flawed software update to the Windows operating system released by US cybersecurity firm CrowdStrike.
Microsoft said on Friday that "all previously impacted Microsoft 365 apps and services have recovered."
CrowdStrike CEO George Kurtz wrote in a social media post that the outage was "not a security incident or cyberattack." He said, "The issue has been identified, isolated and a fix has been deployed."
During an interview on US television, the CEO said he offered a deep apology to customers, travelers and others affected.