Timebomb or time bomb is a software mechanism that renders a computer program unusable after a pre-set period of time. It is commonly seen in pre-release software, where it is used to discourage users from holding onto outdated testing versions.
Windows[edit | edit source]
In Windows 9x-based builds of Windows, the timebomb is activated by
IO.SYS. Once the timebomb is triggered, Windows will display a message on boot saying the pre-evaluation period has expired. Windows will then immediately shut down and will not boot until the operating system is reinstalled with the correct BIOS date (
IO.SYS patches itself on disk to infinite loop). Windows 95 build 216 is the first build to include a timebomb.
In NT-based Windows versions, once a timebomb is triggered, the
END_OF_NT_EVALUATION_PERIOD bugcheck is used to periodically reboot the system. The first build to include a modern timebomb was Windows 2000 build 1627.1, although the Japanese and Korean pre-release versions of Windows NT 3.5 include a warning message box telling the user to install a retail copy of Windows after a certain date, unlike any other builds from the era.
Most builds of Windows 10 version 1507 and 1511 are flightsigned (file signatures take certificate expiry time into account). Should the timebomb activate, the bootloader will be broken due to expiring certificates.
macOS[edit | edit source]
Mac OS X Public Beta is the only known version to include a timebomb. While the timebomb didn't allow the user to log into the user interface, it didn't affect the Darwin kernel or any other components not related to the Aqua interface.