Why won't Apple's original 1TB SSD fit in my JDM 855/825 enclosure? Category : Compatibility To allow for higher capacity, Apple has widened the PCB for its 1TB SSDs, so that compared to Apple's other SSDs, the 1TB SSD comes larger in size. This is why the original 1TB SSD from Apple won't fit in the JetDrive 855/825 enclosure. Is the answer helpful? Related Why does my Mac computer take longer to boot after I upgraded it with JetDrive SSD? Why is the performance of my JDM820/825 lower than specified? Why is the system optimization function displayed as OFF the second time I activate JetDrive Toolbox when the function was turned ON previously? Technical Support If the answer can't help you, you can contact the Tech Support Department Get Started