A storage device in accordance with the inventive concepts includes at least one nonvolatile memory device and a memory controller controlling the nonvolatile memory device. The memory controller includes at least one processor configured to control an operation of the storage device, and configured to perform at least one of a trim operation according a trim command and a garbage collection operation and a risk protection controller configured to perform a risk protection operation that disables at least one of the garbage collection operation or the trim operation according to a risk protection signal internally generated or a risk protection command input from the external device.