John recently added an M.2 drive and adapter to his daughter's computer, but the computer doesn't recognize it. Leo says it's probably not formatted. Go into the Windows installer, then Options, and select the disk partitioner. If he can't see it there, then there's a problem with it. The key is to get a SATA drive. He can get M.2 SATA drives, but he may as well use an SSD drive at that point.