A stunning revelation or horrible event affects a character or someone they care deeply about, leaving them shocked to the point of mentally shutting down for a while, analogous to the Blue Screen of Death. The effect is similar to passing a Despair Event Horizon, but is temporary rather than permanent. Alternatively, if, say, this occurs during a fight, a hero may have a violent outburst, killing Evil Minions and hurling their own companions aside. They may run off and have to be tracked down by their friends for Epiphany Therapy. Alone in a Crowd typically represents a milder, non-disabling form of BSOD; a related trope is Heroic Safe Mode, wherein the hero "defaults" to a fight or flight mindset before rebooting in safety. A Shell-Shocked Veteran may have a BSOD in their back story.
The trope name notwithstanding, the character suffering a Heroic BSOD may not necessarily be a fully-fledged hero. However, if something like this happens to a more ambiguous or mundane character, it is much more likely to be Played for Laughs or just taken less seriously. But a BSOD is never brief or trivial; the effect must involve some kind of total mental shut-down to qualify. Also, an outright villain suffering a similar effect will usually experience a Villainous Breakdown (often involving them going completely crazy instead of shutting down) or a Villainous BSoD (whereby they gain a conscience).
Possible triggers include failing in something crucial such as saving a loved one or being restricted in what you can do to help, being betrayed by a close friend, being forced to make an "impossible" choice (e.g. having to choose between using "evil" methods or laying friends open to attack), or being hit with a Breaking Speech or Armor-Piercing Question. Other tropes such as These Hands Have Killed often overlap. When the trope is Played for Laughs or used for melodramatic effect, the cause can be less substantial; deranged behavior from someone supposedly sane, seeing something completely surreal, or being hit with a Wall of Text, say.
Other people can attempt to reboot the character; Get a Hold of Yourself, Man! may work (especially in the stories where violence is always the answer), as may telling them to Quit Your Whining. The best thing that can happen to a hero suffering from a BSOD is meeting a friendly Warrior Therapist; the worst thing is meeting a hostile Warrior Therapist, as such a foe can ensure that the hero crashes completely, driving them over the edge into the Despair Event Horizon.
Even after regaining some function, a BSOD sufferer may evince a Thousand-Yard Stare, or go into 10-Minute Retirement. In the longer term, a hero may become emotionally comatose (entering an Angst Coma), obsessive and guilt-ridden, mute, or in really bad cases, a jaded violent amnesiac. A really long-term BSOD would be catatonia; Go Mad from the Revelation is the worst case. Those who remain functional but don't find a cure for the problem may eventually find Safety in Indifference or Emotion Suppression; other people may fear that they have become a Fallen Hero.
Comedy and melodramatic uses of the trope (such as a film or game reviewer having a Critic Breakdown) are far less likely to lead to long-term problems; the character simply snaps back after a few minutes. A character in a slapstick comedy show may be thrown into several blue screens in one episode, as a Running Gag.
If opponents discover a character's BSOD trigger, they may employ it as a weapon — although if they over-use it, the victim may wise up and seek treatment. Even comedy characters can find that a BSOD leads to Character Development, marking the start of a series of new experiences, or causing them to revise their world-view. Hope Is Scary is a frequent reaction to the beginning of recovery for any character. He's Back! often marks a character's full recovery, perhaps accompanied by a "No More Holding Back" Speech. Conversely, a character who never recovers has fallen over the Despair Event Horizon.
Compare Heroic RRoD (the physical equivalent), Freak Out, and Deer in the Headlights. If the character is a sweetheart, this trope can be the end result of Break the Cutie. One common reaction is I Think You Broke Him. In Real Life psychology, this sort of thing is known as an acute stress reaction, or a mental breakdown, and is related to Post Traumatic Stress Disorder. If a character goes into the BSOD state because of issues or revelations regarding who or what they are, they're having an Identity Breakdown. If a character starts singing about their (or someone else's) Heroic BSOD, then it's also an example of BSoD Song.
The trope is named in honor of the infamous Microsoft Windows error that indicates that the system has screwed itself big time (the technical term is "stop error"). A particularly literal version could involve a character (preferably a supercomputer or other Artificial Intelligence) literally displaying a Blue Screen Of Death.
Individuals afflicted with this trope are often seen exhibiting the classic Thousand-Yard Stare, with its blank, emotionless expression and unfocused, empty eyes.
