How it works
SATA is a storage interface used by many drives. A typical internal 2.5-inch SATA drive uses separate data and power connections. The physical shape of an M.2 drive does not tell you whether it uses SATA or PCIe; the socket and system must support the required interface.
A practical example
An M.2 SATA drive may fit a socket yet not be detected when that socket supports only a different interface. A desktop SATA drive can also disappear because of a loose data cable or missing power rather than a failed disk.
What to check
Check the exact drive interface and motherboard storage guide. Inspect data and power connections with the system disconnected. Compare a known-working cable or supported port, and note whether using another slot disables particular SATA ports on that motherboard.
Limits and safe next steps
Do not change firmware storage mode casually on a working operating system; the system may no longer boot. If important data is involved, secure a backup before troubleshooting writes. Interface compatibility does not establish the health of the storage medium.