Macs weren’t affected by the infamous Y2K bug, but Low End Mac reports that Mac OS 8 and earlier do suffer from another date-based issue: the Date & Time Control Panel won’t accept dates past 12/31/2019. Even the oldest Macs can reportedly keep time until 6 February 2040 at 6:28:15 AM, but to set the time on older systems you now need to use bbraun’s free SetDate utility. With that, your classic (or emulated) Macs should be good to go for another 20 years.
Along with the Y2K bug, this Y2K20 problem demonstrates how developers often make incorrect assumptions about how long people will use their software. But the world has changed. We’re betting that the reliance on cloud services and dated security certificates will replace date math and storage as the reason modern software will fail to keep working past its freshness date.