Exported .dae models have a cube embedded in them I've made a few models and when I import them into my game using assimp they all have what looks to be the starting cube in the model, usually poking out the side of the model. But when I open the model in blender the model looks fine. All the models are .dae format

Is this something that can happen when exporting models or is it more likely to be a problem with how I import it into the game. 

Sorry if this is off topic, I'm trying to narrow down the possibilities.

:: EDIT ::

Thanks for all the help, it was actually something wrong with my import code, but there was one model that exporting with selected only fixed, there was a random point way out in the corner in one of the models
The most likely reasons are that the cube was either hidden when you exported or on another layer and you just exported the entire scene. One other thing you could try is when exporting, select the model(s) you want to export and tick Selection Only.