• A defective McAfee virus definition update caused a worldwide meltdown of Windows XP PCs in 2010. The update incorrectly identified a critical Windows system file as a virus, causing the antivirus software to quarantine or delete the file, rendering the affected PCs unusable.

• The issue was particularly problematic for businesses and organizations that relied on Windows XP, as the affected machines were unable to boot up or function properly. McAfee acknowledged the problem and quickly released a fix, but the damage had already been done, with many users reporting significant downtime and productivity losses.

• The incident highlighted the potential risks and consequences of faulty software updates, especially for critical system components. It also underscored the importance of thorough testing and quality control measures for antivirus and other security software, to prevent similar widespread disruptions in the future.