Revolt CTD

There has been a long running discussion and investigation of the problem of CTD's occurring during loyalist revolt's in this thread

This article is an attempt to provide a summary of the findings. Thanks should be extended to Dol Guldur and nikolai1962 for their research findings.

Conditions Required for CTD

Conditions are very specific and all must be present for a CTD to occur:

• Revolt must be a "Loyalist Revolt" - eg to previous owner or faction creator (not rebels)

• Mercenaries must be available to hire in region

• City garrison must be either zero, or two or more units - presence of one unit on its own appears to prevent CTD

• The faction the city is about to revolt to must have no buildings with active recruitment lines within the city

Notes:

"active recruitment lines" can be difficult to explain, you must imagine you control the faction the city is about to revolt to:

If when you took control of that city you could add unit to recruitment queue, then there would not be a CTD on revolt, instead a new garrison of units including the recruitable units and mercenary unit would be formed.

If you could not recruit any unit after gaining ownership, because either; necessary buildings were not built, were previously destroyed, or previously damaged to extent that you could not immediately add unit to queue, then you would have CTD before gaining control.

If one garrison unit of previous owner is present it is ejected from city on revolt

- if with the above mercenaries are also available a revolt garrison is formed comprising multiples of the available mercenaries

- if with the above mercenaries are not present the city revolts to an empty garrison

If mercenaries are not available in region the city can also revolt to an empty garrison without CTD

In Alexander, if faction restricted mercenaries are used, the CTD only occurs if a merc is available to the faction that the settlement is about to revolt to.

Why CTD Occurs in Mods

Many mods choose to remove the option of recruiting peasants via the core (indestructible) building, many also make recruitment of units in recently gained regions more difficult via zone of recruitment systems. Both of those factors mean that it is more likely that the revolt faction will not have an available recruitable unit.

Human players tendencies to destroy any recruitment buildings they can and abandon cities they think they are likely to use also exacerbates the problem. Human players can fix the problem by either not destroying all recruitment buildings or by leaving one (and only one) unit in cities liable to revolt.

However the CTD has also been reported on AI turns though, so a solution should be found to prevent that.

There is still some debate about how the use of units available through core (government buildings) may help to avoid CTD, the writers' opinion is that if the core building is damaged to the extent that the unit is not available then CTD can still occur. Whether or not CTD can occur in vanilla game under these conditions needs verification.

Possible Fixes

This section needs writing up properly

To prevent problems on the players turn, the player can be instructed to leave one unit (and only one unit) in cities about to revolt. To fix problem that can occur on AI turn a modding solution is required:

For the way End of Days fixed the problem see this post

For a screen-shot of the over-large tga idea which was developed by The Fourth Age: Total War see this post