CrystalDiskInfo – free HDD & SSD health monitor
CrystalDiskInfo is a zero-cost, portable utility that reads your drive’s S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) data and translates it into plain-English status, temperature and lifetime statistics. It works with traditional spinning disks, SATA/NVMe SSDs, USB enclosures and even RAID volumes, giving you an early-warning dashboard before a crash costs you data.
What it shows (at a glance)
- Overall “Health Status” – Good, Caution, Bad or Unknown.
- Current, worst and threshold values for 20–30 key attributes (re-allocated sectors, pending counts, wear-leveling, total host writes, etc.).
- Drive temperature, power-on hours, start-stop cycles, firmware version, interface speed, serial number.
- Graphs that plot temperature over time—handy for spotting cooling problems.
Why keep it running?
- Pro-active alerts – optional pop-up, e-mail or sound warning when any attribute drops below vendor limits.
- Portable & silent – single 5 MB EXE, no installer, no ads, no phone-home; drop it on a USB stick and check any PC in seconds.
- Beginner-friendly – green/blue/yellow/red colour coding tells you instantly if the disk is safe or dying.
- Advanced details – hex view of raw attribute data, AAM/APM control, NCQ queue management, S.M.A.R.T. self-tests on demand.
- Extensible – themes, plug-ins and command-line switches let power-users integrate it into scripts or Rainmeter skins.
Typical warning signs
| Attribute | What it means | Action |
|---|---|---|
| 05 Reallocated Sectors | Drive retired bad blocks | ≥ 10 → start backup |
| C5 Current Pending | Unstable sectors waiting remap | ≥ 1 → monitor daily |
| E7 SSD Wear Levelling | % life left | < 10 % → replace soon |
| Temperature > 55 °C | Accelerates ageing | Improve airflow |
Quick start
- Download the ZIP (portable) or installer from the official site.
- Run
DiskInfo.exe; grant admin rights if you want NVMe health data. - Look at the top line—anything except “Good” deserves attention.
- Enable automatic startup + temperature alert in Function → Advanced Feature → Alert Settings.
Bottom line
CrystalDiskInfo is the easiest way to turn cryptic S.M.A.R.T. numbers into a simple traffic-light verdict. Keep it on every PC and you’ll know which drive to replace before the blue-screen of death arrives.