The Y2K Problem, also known as the "Millennium Bug," prompted global concerns in 1999 that computer systems would malfunction at the turn of the millennium. Systems designed to process only two-digit years risked reading "00" as 1900 instead of 2000. The potential for widespread errors led to a massive effort to update software and hardware, ensuring continuity in critical services like power, finance, and healthcare. The event spurred improvements in date-handling and IT infrastructure.