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 can't I upgrade or install MacOS Monterey on my JDM? JetDrive fails to restore operating system and the partition of the original drive is grayed out. What can I do? Is there any way that I can clone my Mac OS to JetDrive SSD? Technical Support If the answer can't help you, you can contact the Tech Support Department Get Started