System failure is an event that occurs in the Swan station a few seconds after the Countdown Timer reaches zero. Once the Hieroglyphs are all displayed, the electromagnetic force near the concrete wall in the Hatch begins to build rapidly, pulling any and all magnetic metallic objects inward from increasingly great distances. (Non-ferromagnetic metals, such as copper, aluminum and brass are not visibly affected; this is why Desmond's key was not affected by the force.) The words system failure repeatedly scroll across the screen of the Computer and a corresponding printout of the event is produced at the Pearl. The speakers also repeat "System Failure".
If the Computer is intact, there remains time to enter the numbers and prevent further damage.
At least two system failures are known with certainty to have occurred:
- On September 22, 2004 at 4:16 (dated by the log printout), also the day of The Crash, a.k.a. Day 1. Desmond believes that he caused the crash of Flight 815 when his absence from the Hatch led to a brief system failure.
- On November 26, 2004, when Locke decides not to Push the Button. After Locke causes the Day 66 system failure, Desmond attempts to rectify the situation by using the fail safe. This in turn is followed by The Discharge.