A portable storage device 10 includes a body 12, an actuator 16, and an indicator 18. When coupled to a host device 22, a user depressing the actuator 16 causes an interrupt message to be sent to the host device, which initiates shutdown of the portable device by removing it from a host device list of available storage media, and de-powers the portable device. The indicator then changes to signify that it is safe to remove the portable device from the host. The indicator may be visual, aural, or tactile. Preferably, the indicator uniquely identifies four states regarding the status of computer instruction exchange between the portable and host devices, including normal and inactive, normal and active, error, and ready-to-be-removed states. The latter is available only after actuating the actuator. Removal of the portable device is thereby effected by a single user action at the portable device: depressing the actuator.