Horrible post title, but i will try to explain.

When creating a ship class in the ShipClassDefs.xml file - so that the game will create auto-designed versions - and you use an user-made design (template) that is created with only techs available at the start of the game, then no ship (version) design is created upon game start.

Lets say i have a design called "Voyeur", and made a template of it, and have created a ship class ("TerranVoyeur") for this ship template, and this ship class is added to the faction definition (FactionDefs.xml). However when i start a new game the "Voyeur M1" design is not automatically created and the following message will appear in the debug.err file:

Debug Message: Ship Design: Missing ship design for ship class auto-upgrade TerranVoyeur. Was this caused by pointing to a custom ship design? Blueprints must point to core or modded ships.

If i do not move the design files then the ship design will be instantiated on the first ship/weapon tech researched. This is the same as if the ship incorporates a non-game-start-available-tech and is waiting for that tech to be researched.

It appear as if the custom design directory is processed after the initial auto-ship-designer task has run, because as seen in the debug.err file core ship designs are instantiated before the user (ship and template) designs are loaded.

@Ray,

Ticket already submitted.