Improper seating is the most common reason an SSD isn't recognized. Ensuring it is correctly connected resolves the issue. * Why Not A (Faulty SSD): A faulty SSD is possible but less likely than an installation issue. * Why Not B (Not formatted): Formatting affects data usability, not drive detection. * Why Not C (Incompatibility): SSD compatibility issues are rare with modern hardware. CompTIA A+ Exam Reference: Core 1 (220-1101), Section 3.3, storage troubleshooting.