Exception

In computer programming and video gaming, an exception is simply an error—an event where something goes wrong. Exceptions are common occurrences in most software, rarely ever producing noticeable errors; those that bring the primary processes of a program to a screeching halt (e.x. crashing or freezing the program) are known as fatal exceptions.

Fatal exceptions are quite common in Halo PC, and are also frequently encountered when modifying Halo: Custom Edition maps. Generally, they occur when something happens and the game's programming doesn't account for it; in this sense, the exceptions are effectively the result of a glitch. In the Halo community, the word "exception" is generally understood to refer to fatal exceptions.

Halo PC
A good example of a fatal exception in Halo PC is when text such as team talk is submitted after a game has closed down, Halo will minimize and a window will open with the text "gathering exception data". After this window has been closed, Halo must be restarted, for the program cannot be reopened. This event is very rare, but has happened.

Another example of how exceptions occur is when you are using the Halo Map Tools to mod Halo PC/XBOX maps. The game and tools use "meta tags" to direct the game engine to different objects, like AI spawns, weapons, vehicles, scenery and projectiles. This will happen a lot as if you attempt to copy a Bipd tag from one level to another.

Another example of an exception error is using Halo: Hacking Tools. Let's say a player makes a cyborg AI and makes him spawn in a banshee simply by going to the banshee tag and editing the meta. If a player changes the actor variant to cyborg. The AI cyborg will attack the player in a banshee, and can exit the vehicle and shoot at the player. However, if the player enters that banshee, an exception error will occur.

Another example is modding and selecting a saved game. To successfully modify a level and play it, the level must be restarted; a saved game cannot be played from another version of the map. If it is attempted, the game will throw an exception.

Types of Exception Causes in Halo PC

 * Making maps and cutscenes unplayable.
 * Modding certain items, such as Hunters.
 * Animations not working or not existing.

Halo PC (Demo)
Players can get exceptions when they unsuccessfully attempt to modify Halo PC's demo/trial version. Exceptions will also occur if campaign or multiplayer map data does not match Blood Gulch or The Silent Cartographer respectively - the only two maps in the demo.

Players may edit the properties of these maps by modding, which can occasionally force an exception when the game starts up. The likelihood of such an error increases when modders use two sets of contradicting data—that is, if a modder tries to import an object from a map not present in the Halo PC Demo, and then place that object inside of a map that is present in the demo. To avoid such an exception, demo modders should stick to using items already in the demo.

Halo: Custom Edition
Exceptions are often encountered when using user-created maps or programs. Not all modders check for glitches or exceptions when creating maps. For example, in the map "Hunter Territory" (where a player can play as a Hunter), if you somehow die or if you restart the game, everyone will get an exception. Exceptions can also happen if Developer Mode is turned off while playing that map. Entering a single-player Campaign on multiplayer will lead to an exception error.

The Developer Mode "Bump Possession" cheat can also be used to cause an exception by taking control of a Marine and trying to drive a Warthog that is carrying other Marines; this is likely because Marines were never meant to drive Warthogs with passengers, and either lack the appropriate animations or the appropriate AI for doing so.

"Bump Possession" can also cause an exception in multiplayer games, if a player tries to bump possess another player or (if available) an AI-controlled NPC. Developer Mode can also lead to exceptions if a player-spawned vehicle respawns on a map that lacks spawn points.

Exception errors can also occur when overloading the map with objects such as Flood NPCs. When a player adds too many Flood, they will form a large group. Taking out more than one at a time will cause an exception, due to the fact that there are simply too many objects in the map for the game to handle at one time.