On 19 July 2024, a faulty update to security software produced by CrowdStrike, an American cybersecurity company, caused many computers and virtual machines running Microsoft Windows to crash, affecting a wide range of users, including airlines, airports, banks, hospitals, stock markets, and broadcasting services. The error was discovered and a fix was identified on the same day, but the outage continues to delay airline flights, cause problems in processing electronic payments, and disrupt emergency services. The incident has been characterised as the “largest IT outage in history”.
Long ago when I worked in enterprise IT management, the largest customers had ~500k endpoints under management, something like 90% Windows.