Checking a hard drive or SSD’s S.M.A.R.T. attributes is a bit geeky and the output is a bit arcane, but fortunately, there are tools that make it easy to check the data and interpret it. In fact, while you can deep dive into the individual attributes if you’re so inclined, you don’t need to do so to use the tools and get actionable feedback on the health of your SSD or old HDD.

The biggest thing to remember when running S.M.A.R.T. tests on different types of drives is what the tests measure. S.M.A.R.T. tests for mechanical hard drives include data points for things related to the moving parts of the drive and the effect of motion on them (number of times the drive has spun up, failed to spin up, experienced shock or sudden stoppage, and so on).

SSD drive health (including NVMe drives, which also use solid-state memory) is almost entirely focused on lifetime read/write data. Unlike mechanical hard drives that tend to die from physical wear and tear, SSDs and NVMe drives—barring a blown electrical component or something catastrophic—die from eventually exceeding their Terabytes Written (TBW) rating. The health of your SDD is almost entirely a reflection of how much data has been written to the solid-state memory inside it.

Check S.M.AR.T. Status with CrystalDiskInfo

CrystalDiskInfo is a free easy-to-use open-source Windows application that will show you S.M.A.R.T. attributes for mechanical hard drives (HDD), solid-state drives (SSD), and Non-Volatile Memory Express (NVMe) drives. The application is available as a portable app or with an installer.

Conduct a One Time Test with CrystalDiskInfo

There are two layers to using CrystalDiskInfo, simply running it and getting a “Yup, everything looks good” feel for things by checking the general “Health Status” of each drive, or by digging into the individual S.M.A.R.T. attributes if you are curious.

The general health status is indicated by blue for “Good,” yellow for “Caution,” and red for “Bad.” If your drive health is good, there isn’t much to do beyond check out other stats because you’re curious. If your drive health is flagged with “Caution,” you should back up your data and make plans to replace the drive. If your drive health is “Bad,” you should approach data backup with a delicate touch (check out the section below about what to do if your drive is dying for a more detailed look).

At the top of the window interface, you can also check the drive temperature and see stats about the drive, like power on count, power on hours, and more.

Do note, when looking at the screenshot above, that the drive shown there is a mechanical hard drive, a Western Digital 14TB media storage drive. You’ll notice that there is no data points for total data reads/writes because that isn’t a metric used to gauge HDD health.

In the screenshot below, however, you can see the same CrystalDiskInfo S.M.A.R.T readout for a Western Digital SSD. Because SSD drive health is based on different metrics than tradtional driv health, different data points are emphasized.

When you look at S.M.A.R.T. data for SSD and NVMe drive health, you’ll see “Total Host Reads,” “Total Host Writes,” and if the manufacturer uses the particular attribute, “Total NAND Writes.”

The drive health of your SSD is, primarily, based on how close you are to exceeding the manufacturer’s Terabytes Written (TBW) rating for the drive. In the case of the Western Digital 1TB Blue drive we see in the screenshot above, the TBW rating is 400TB. Despite being several years old and having a total power-on-time just shy of a year of total operation, the drive is only at 0.15% of it’s total TBW rating.

In addition to the information presented at the top of the dashboard, you can also view a list of detailed information about each drive by reading down the list of S.M.A.R.T. attributes.

Configure CrystalDiskInfo for Automatic Ongoing Testing

There isn’t much to mess around with in CrystalDiskInfo if you’re just checking the S.M.A.R.T. data now and then. But if you want the app to run in the background and keep an eye on the health of your drives, you can switch a simple toggle.

In the Function menu, check “Resident” and “Startup,” as seen in the screenshot below.

“Startup” will launch CrystalDiskInfo when you start Windows and “Resident” will park the app, in the form of an active drive indicator, in the Windows System Tray.

Check S.M.AR.T. at the Command Prompt

At the prompt,  type (or copy and paste) the following command, and then press Enter:

wmic diskdrive get status

If everything is working properly, you should see the status “OK” displayed for each hard drive on your system. Other statuses—such as “Bad,” “Caution,” or “Unknown”—can indicate problems with your drive or errors retrieving S.M.A.R.T. information. Anything other than an “OK” response should prompt you to use a more detailed tool like CrystalDiskInfo to investigate the drive health.

If the S.M.A.R.T. status indicates that you have an error or your SSD is in poor health, it does not necessarily mean that your hard drive will fail immediately. Just like the check engine light on your car doesn’t mean the car is about to fail catastrophically, a S.M.A.R.T. error or two doesn’t mean the drive is about to spontaneously combust.

However, if there’s a S.M.A.R.T. error, it would be wise to assume that your SDD is in the process of failing. The attributes are calibrated to industry and manufacturer standards and intended to help you diagnose drive failure ahead of schedule and stave off data loss.

A complete failure could come in a few minutes, a few months, or—in some cases—even a few years. However long it takes, you should not trust the hard drive with your data in the meantime.

Ensure you have up-to-date backups of all your files stored on another media, such as an external hard drive or optical discs. Obviously, this is good advice whether you know the S.M.A.R.T. status of your drives or not. Problems—including drive failure—can happen at any time, and without warning.

With your files properly backed up, you should look into replacing your hard drive or SDD as soon as possible. You simply cannot consider a hard drive that fails a S.M.A.R.T. test to be reliable. Even if your hard drive doesn’t die completely, it could corrupt portions of your data. You might also consider using the chkdsk tool in Windows to diagnose and repair any related problems that it can.

Finally, there is one key strategy to use when backing up data from a severely compromised disk throwing up multiple red-flag S.M.A.R.T. statuses. Don’t attempt to back up the entire disk at once immediately, as the sudden influx of read/write operations can push it over the edge. Instead, focus on backing up the most crucial files first. Things like your family photos and important documents should be backed up first.

Once you have crucial files backed up on a removable drive or other media, you can clone your existing hard drive to a replacement drive. If the drive fails during the process, your critical files are backed up. If the drive lives long enough to complete the process, you now have a brand drive with all your files and settings intact.

Frequently Asked Questions About Hard Drives, SDDs, and S.M.A.R.T.

Have more questions about S.M.A.R.T. attributes and how they relate to the health and longevity or your hard drives and SSDs? You’re not alone. Here are some of the most common questions we get about the topic.

How Accurate Is S.M.A.R.T. Data?

S.M.A.R.T. data is based on industry data that indicates a drive is at an increased risk for failure. The models are based on predictability, and the data can help you deal with predictable failures. A Google study on S.M.A.R.T. data found that key attributes did, in fact, strongly indicate impending disk failure.

S.M.A.R.T. data cannot, however, warn you of “unpredictable” failures. It can warn you of signs that a drive spindle is going bad or the chips in your SSD are failing based on collected data, but it can’t predict failures as a result of power surges, spontaneous failure of a component on a drive’s control board, or other unfortunate events.

If the S.M.A.R.T. Test Says My Drive Is Bad, Should I Replace It?

While a failed S.M.A.R.T. test is not a kiss of death, the test is calibrated specifically to give you useful information. If the drive health has degraded to the point that the test application is telling you the drive health is bad, then you should listen.

We would consider that advice doubly important when dealing with solid-state drives. SSDs are very durable and have a very long lifespan under regular daily consumer use in a home PC or laptop.

If you run a S.M.A.R.T. test and get an alert your SSD is in poor health, you should consider the drive on its last legs. A “bad” or “failed” health status report for an SSD drive indicates that the drive has exceeded its manfacturer’s lifetime operational threshold. While the drive may continue to operate without errors, we would not trust it with anything critical.