Hi fisher13, I've had dreams in large warehouses before; not searching through boxes though, usually chasing someone or being chased myself like in the movies - I think they use warehouses/factories a lot in sci fi movies, which I'm a big fan of and explains to a certain extent why I have such dreams.

Normal houses that you live in usually represent yourself, or your psyche - with different rooms symbolizing different aspects of yourself and thoughts and emotions.

Warehouses are kind of similar to normal houses; in waking life they store things, like the boxes you were seaching through; in dreams warehouses store your memories and thoughts and can represent your hidden resources and energy. If the warehouse is empty it can mean that you need to replenish your resources of energy.