The Facts

• A glitch with Microsoft Windows on Friday reportedly hit global businesses and institutions, disrupting critical services — including airlines, banks, and stock exchanges — across the world.

• The massive IT outage canceled at least 500 US flights, affected operations at London's Stock Exchange, grounded Sky News, and impacted Europe's medical facilities.

• Cybersecurity firm CrowdStrike said that the outage had been caused by "a defect found in a single content update for Windows hosts," adding it was neither a security incident nor a cyberattack.