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? Should I purchase a Jetdrive with larger capacity than the original Mac SSD/HDD if I want to clone the system with Disk Utility? Why can't I boot from my JetDrive SSD after system migration? Technical Support If the answer can't help you, you can contact the Tech Support Department Get Started