A:Answer Other answer is not 100% accurate. While you cannot install a 2.5" HDD like you can in some other non-ultrabook laptops, this laptop does have an open PCIe NVMe SSD slot where you can install a 2nd NVMe SSD up to 2TB, bringing the total SSD capacity to 2.5TB. If you swap out the 1st NVMe SSD as well, you could in theory use two 2TB NVMe SSD's for a total of 4TB.