More details:

• Windows PCs all around the world are crashing, and it's getting uglier fast.

• The issue is due to a issue with CrowdStrike's Falcon Sensor software, and it's spreading in unpredictable ways.

• CrowdStrike is a cybersecurity company, and Falcon Sensor is software designed to prevent computer systems from cyber attacks. Earlier this morning, on July 19, the company warned its users that Windows systems are "experiencing a bugcheck/blue screen error related to the Falcon Sensor," and said that its engineering teams are "actively working to resolve this issue."

• Apparently, an update to the Falcon software is what caused the issue; the company rolled back the update but numerous machines are still affected.

mashable.com/article/crowdstrike-microsoft-outage-windows-blue-screen-explained