Signs of hard drive failure
Separate harmless quirks from urgent warnings—then clone before you chase bad sectors with destructive tests.
Acoustic fingerprint
Single clicks during power events differ from rhythmic clicking every few seconds—the latter often precedes head stack trouble. Listen after eliminating PSU ripple and loose screws rattling against trays.
Latency ghosts
Explorer freezes while SMART still looks “fine” can mean the disk retries reads obsessively. Watch OS-level latency counters—sometimes they move before SMART crosses thresholds.
SMART slopes
Sudden jumps in reallocated or pending sectors deserve immediate backup verification—even if overall health percentage barely moved.