Internal Error

Tiberian Sun's Internal Error

Red Alert 2's Internal Error

Yuri Revenge's Internal Error

RockPatch's Internal Error

The Internal Error (often just written short-hand as IE) is a general error returned by the Tiberian Sun engine and its derivates. The message itself gives no information about what the error actually was or what went wrong, thus leaving it to the modder to know what could have caused the error and to find the cause in their mod's changes.

If you experience an Internal Error, you should:
1. Check if the EIP reported in your except.txt file matches an EIP for which the IE cause is known (see below). 2. Think about whether a distinctive event immediately preceeded the error (e.g. a unit being built, a weapon being fired, etc.). If this was the case then take a look at the changes you applied to that unit/weapon/whatever and see if there are any mistakes.
3. Carefully check your latest modifications, with the help of a diff between the current rules set and the previous, working rules if possible (for this reason, and in case you mess up your code beyond repair, you should always keep recent backups of working code). Remember that the more code you add at the same time, the more likely it is to introduce multiple bugs and IE causes (and just because you found one mistake in your code, that doesn't mean there can't be another).

Except.txt

If your game crashes because of an Internal Error, a file named except.txt is generated in your game folder. This file is a dump of certain runtime-data from the game at the moment the error occurred and could potentially tell you exactly what went wrong if you knew the engine code.
Due to his research into the game's binary and his efforts to develop the RockPatch, pd has occasionally been able to indicate the area of the engine where the error occurred (for example, an error occurring in the voxel-loading routines may indicate a problem with a custom voxel). However, pd has other commitments and should not be treated as the go-to guy for any IEs you may have. Further more, pd may not neccessarily be able to help - without the source code or a comprehensive understanding of the game's binary the file is of little use. (cp. SYNCx.txt)

According to an early version of Except.txt (which now redirects here), this file includes the full structure and a stack dump of a CONTEXT element.

IEs that share the same cause also share the same EIP: value in except.txt, so knowing that value might help you determine the cause of your IE. See the list of known IE causes (below) which also includes the corresponding EIP.

List of known causes of Internal Errors (and their EIPs) (please expand)

Since "Internal Error" is the game's response to almost any fatal error, its causes are diverse. Most common are causes related to weapons and warheads, with a missing warhead probably being the most commonly reported cause.

Yuri's Revenge 1.001
EIP	Weapon-related Cause
?	An object has been assigned a weapon that does not exist (see 'broken-reference causes', below).
006F3481	The (elite) secondary weapon (or its warhead) of the object you just selected could not be found (see 'broken-reference causes', below).
0046650D	You have a shrapnel weapon which isn't assigned to a dummy object (see 'broken-reference causes' below).
?	A unit in a game mode override file has a weapon that isn't assigned to a dummy unit in the main rules (see 'broken-reference causes', below).
00772A98	Firing a weapon that has no projectile (see 'broken-reference causes', below).
?	When a unit is able to occupy buildings and it has a chrono weapon, an IE occurs when that weapon is fired.
004145BD	An InfantryType has been given a spawn weapon (such as ASWLauncher).
00471CA4	NEEDS TESTING. Not sure about the details of this one, needs clarification: A unit whose Primary weapon had Suicide=yes and Secondary had multiple mind-control. Selecting the unit and hovering the cursor over an enemy caused an IE. Swapping Primary and Secondary prevented the IE. Later, after tweaking the unit to try and determine the precise cause, got the same IE the instant it was built.
EIP	Warhead-related Cause
006F40A2	Having a weapon's Warhead tag point to a warhead that doesn't exist (e.g. through a typo), or having no warhead-tag at all (see 'broken-reference causes', below).
004895C7	You have a warhead with a Template:TTL greater than 11.
?	Setting off a warhead with a CellSpread that also has Template:TTL set.
0071AF4D	You have a shrapnel weapon with a Template:TTL warhead.
?	Warheads that are not listed under [Warheads] can cause an IE, although some modders have found that this isn't always a problem.
EIP	Cause
?	An MCV turns neutral: If a player's MCV was mind-controlled by an enemy, that player is killed, and the MCV is then released from mind-control, an IE will occur. The cause is probably due to the Civilian house not being designed to handle MCVs. The only workaround is to make MCVs immune to mind-control (this is done in the YR 1.002 UMP). Neutral Construction Yards do not seem to cause a problem.
?	If a falling paratrooper (who has nearly reached the ground) is killed by an area-effect mutation weapon. Point based mutations seem to be okay (the falling paratrooper explodes) and the Genetic Mutator seems incapable of killing falling paratroopers. If you have an area-effect mutation weapon, you should ensure that all paratroopers are immune to it (this also means that you can't have a buildable paradrop plane and an area-effect mutation weapon in the same mod).
0050CE5C	The AI used a Weather Storm or Nuclear Missile superweapon and a building exists on the map with Template:TTL=yes set. You need to uncomment/restore the [[[:Template:TTL]]] → Template:TTL line.
0050CE14	You have a BuildingType with Template:TTL, but you need to uncomment/restore the [[[:Template:TTL]]] → Template:TTL line.
?	Omitting Template:TTL on InfDeath 9's animation (Template:TTL) can sometimes cause an IE. See MakeInfantry for more information.
?	Using the 'Sell Unit' super weapon on a tank-bunkered unit breaks the Tank Bunker. Attempting to sell or destroy the broken Tank Bunker causes an IE. The only way to prevent this is to make sure a player never has access to both the Sell Unit Super weapon and the Tank Bunker at the same time (so unless both buildings are country specials, that means removing MCVs from crates and making Construction Yards uncapturable and immune to mind-control).
?	Adding a new harvester for a 4th side/faction and not making an AI Trigger for it.
0073B0C9	The concept known as "Infantry Linking" can result in an IE, occuring when the linked infantry was modified in a subsequent game mode override file or a map and a human player scrolls their battlefield view to a place on the map where an AI-owned War Factory is located. Don't do Infantry Linking.
?	If you have a buildable Construction Yard, start its construction, and then cancel it, an IE will occur. Construction Yards should not be buildable - they should only be deployed from vehicles.
?	Calling for an animation that is not listed under [Animations] might trigger an IE.
?	Building a unit in-game whose VXL/SHP was inserted in an original game MIX instead of an expansion MIX.
005D7387	Not having at least one valid InfantryType with Template:TTL (default) for each house.
?	Setting Template:TTL. Default value is -1, positive values do not cause an IE.
0042E7AF	A Construction Yard not having Template:TTL set when the owning side's AI is present in a game.
?	Removing a building from the PrerequisitePower= list, while it exists in one of the (GDI/NODRegular/Third)PowerPlant= lists will cause an IE the moment any of your Power buildings get destroyed or sold as long as you own a Construction Yard. YR mods that remove Yuri's side from the game, should not remove YAPOWR from PrerequisitePower=.
?	If an overlay type with Template:TTL is destroyed and the Template:TTL tag is blank or missing.
?	Placing two buildings on a map so that they overlap (in the map editor), and then destroying or garrisoning one of them (in-game). Use FinalAlert's Options → Show Building Outline feature to see the actual areas taken up by buildings, since there are a lot of buildings whose foundation is different from their visual size.
004242DB	Using a TrailerAnim on an animation but not setting a TrailerSeperation (or setting Template:TTL). This is because the default TrailerSeperation is zero, and that number is used as a divisor.
007120F7	You have a BuildingType (which is click-repairable) with Template:TTL or Template:TTL below [[[:Template:TTL]]]→Template:TTL.
0062B662	Having an animation with Template:TTL which does not point to a valid ParticleSystem (see 'broken-reference causes, below).
006AEBB8	Your ra2md.ini file lists a combination of mpmode/map which the game cannot satisfy.
004F8CCD	You've listed less than 3 BuildingTypes at BuildConst= in [AI] Section and lost or sold your last listed Construction Yard while on low power. If you've already lost it, the IE will trigger when you run out of power after that.
00441C28	You have set ShakeScreen to zero.
90900004	Generic exception, for example, raised when you are missing the snowmd.ini median fix.

Tiberian Sun 2.03
EIP	Cause
00415698	You used a TrailerAnim on an animation but forgot to set a TrailerSeperation.
006717CB	WaveClass laser exception. No certain fix for this as we know, it is a possible error with the games code.
0067159B	WaveClass Sonic exception. Not sure if this is code related, could be end user.
006703D4	WaveClass Sonic exception, normally triggered by a unit with a weapon that has IsSonic=yes set, firing to the south of the screen and the user scrolling up. No certain fix for this as we know, it is a possible error with the games code.
004C6428	AI does not have any buildings available for it to build. Check Template:TTL=, Template:TTL= etc.
90900004	Generic exception, for example, raised when you are missing the snowmd.ini median fix.

Broken-reference Causes

• Most of the flags that point to an object type do not verify that the object type exists and will try to invoke it anyway. This includes pointers to weapons, projectiles, warheads, particles, particle systems and infantry/unit/aircraft/building types, among other things.
• All object types must be parsed in order for them to be invoked successfully. For example, a weapon must be parsed by being referenced by a unit in the main rules (weapons used in a game mode that aren't referenced in the main rules will not have been parsed, nor will shrapnel weapons that haven't been referenced by a dummy unit).

Footnotes

¹ ↑ The RockPatch does allow higher values (depending on version).

Software used to find Internal Errors

• INI Checker (can check your rules, art and sound files for syntactic errors like typos and missing references)
• ExceptChecker (primarily for RockPatch-related IEs, it analyzes except.txt, tries to find references to code added by the patch or known routines, and might then be able give a direction)
• Debugger (if you know assembler)

See also

• Reconnection Error
• Confirmation the Infantry Linking IE also applies to modifications done by maps