An electrically heated aerosol-generating system is provided, including a primary device and a secondary, aerosol-generating, device having a cavity at a proximal end configured to removably receive an aerosol-generating substrate. The primary device includes a housing; a power supply; a cavity in the housing configured to receive the secondary device; a plurality of electrical contacts within the cavity, each contact being configured to contact a corresponding contact of the secondary device when the secondary device is in the cavity, at least one of the contacts being connected to the power supply; and a lid configured to cover an opening of the cavity, and being moveable between a first closed position, and a second open position. The lid includes a protrusion configured to prevent movement from the second position to the first position if the secondary device is inserted incorrectly.