Hard Drive S.M.A.R.T. Bad Health Warning – Real Fix

EP
Erropedia Team
📅 June 27, 2026 📅 Updated Aug 2, 2026 👁 8 views Hardware – Hard Drives Intermediate
Your hard drive shows bad health in S.M.A.R.T. It's usually a reallocated sector count issue. Here's how to check and fix it without wasting time.

Scenario – When This Error Hits

You boot your PC and get a warning from the BIOS or Windows: "S.M.A.R.T. status bad, backup and replace." Or you open CrystalDiskInfo and see a yellow or red status for "Reallocated Sectors Count" or "Current Pending Sector." This usually happens after a sudden power loss, a crash, or just aging on an old spinning drive (HDD). I've seen it most on 1TB+ drives from 2015-2019 models.

Root Cause – What's Actually Happening

The drive's firmware marks bad physical sectors and moves data to spare ones. That's reallocation. S.M.A.R.T. tracks how many spares are left. When the count climbs, the drive is dying. The culprit here is almost always physical damage – a head crash, a bad platter spot, or degradation over time. You can't fix bad sectors with software. Anyone telling you otherwise is selling snake oil. The real fix is to stop the drive from getting worse and replace it.

Fix – Step by Step

  1. Backup everything now. Don't even think about running diagnostics first. Copy your data to another drive. If the drive fails during testing, you lose everything. Use a USB enclosure or SATA-to-USB cable if needed.
  2. Run a S.M.A.R.T. test from the manufacturer's tool. Skip Windows' built-in checkdisk – it's slow and won't tell you the real story. For Western Digital drives, grab WD Data Lifeguard Diagnostic. For Seagate, use SeaTools. For others like Toshiba or Hitachi, try GSmartControl (works with most brands). Run the "Extended Test" or "Long Test." It takes hours, but it's the only way to confirm if the drive has mechanical damage.
  3. Check the raw values. Open the S.M.A.R.T. attributes in the tool. Look for these:
    • ID 05 – Reallocated Sectors Count: If this is above 10, the drive is failing. Above 100? Replace immediately.
    • ID C5 – Current Pending Sector Count: If this is non-zero, the drive is actively trying to remap sectors but failing.
    • ID C6 – Uncorrectable Sector Count: If this is >0, data is already lost.
  4. If the test fails or raw values are high, replace the drive. No software can fix physical damage. Don't bother with low-level format or HDD Regenerator – they might mask bad sectors temporarily, but the drive will fail again. I've seen people lose data trying this.
  5. If the test passes and raw values are low (under 5 for reallocated sectors), the drive might still be usable for non-critical data. But keep monitoring it weekly. Run S.M.A.R.T. tests automatically with HD Sentinel or CrystalDiskInfo and set alerts.

Still Failing? – What to Check Next

If you've done all that and the warning keeps popping, check if the drive is under warranty. Most HDDs (especially Western Digital and Seagate) have 2-5 year warranties. Check the serial number on the manufacturer's site. If it's covered, RMA it – they'll send a replacement for free. If not, the drive's done for. Don't try to revive it. I've wasted days on dead drives. Replace it with an SSD if you can – they're more reliable and silent.

Quick note: If the drive is an SSD rather than an HDD, S.M.A.R.T. bad health can be caused by NAND wear (TBW exceeded). Same rule applies – backup and replace. SSDs don't have spinning platters, but they have a limited write lifespan.

One last thing: never use disk utilities from different manufacturers. Running a Seagate tool on a Western Digital drive can corrupt the firmware. Stick to the brand's own tools. I've seen drives bricked that way.

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EP
Erropedia Team
Tech Support Editors
The Erropedia editorial team researches and documents real-world tech errors from across Windows, Linux, macOS, networking, databases, cloud platforms, and more. Every solution is reviewed for accuracy and updated as software and systems evolve.