Complete Drive Test stops at 90% complete

Running a Complete Drive Test—whether using built-in utilities like Windows CHKDSK, WD Data Lifeguard Diagnostics, Sea Tools, or another diagnostic tool—is a critical step in verifying the health of a hard drive or SSD. But what happens when the test hangs or stops at 90% and doesn’t complete? This is a surprisingly common issue that can indicate anything from minor bad sectors to full hardware failure.

Let’s explore why a drive test might stall at 90%, what it could mean, and how you can proceed.

What Is a Complete Drive Test?

A Complete Drive Test, sometimes called an extended or long diagnostic test, scans the entire surface of your drive for:

Bad sectors

Read/write errors

Controller issues

Slow responding blocks

It’s much more thorough than a quick or SMART test and often takes hours to complete, depending on drive size and condition.

Why Does It Stop at 90%?

When a test stalls at 90%, the issue is usually related to unreadable or slow sectors near the end of the drive’s surface. Here are some common reasons:

1. Bad Sectors Detected

The drive may have developed bad sectors near the 90% mark, which the tool is trying—and failing—to read or repair.

2. Slow or Pending Sectors

Unlike bad sectors, pending sectors are not yet marked as unusable. If the drive struggles to read them, the test can hang for a long time.

3. Mechanical or Electrical Problems

For HDDs, issues with the read/write heads or spindle motor can affect drive performance and interrupt tests. SSDs might show issues with their memory blocks or controller.

4. Firmware Glitch

A bug in the drive’s firmware could also cause a test to stall when accessing certain data ranges.

5. Software Conflict

Antivirus software, backup tools, or even Windows background processes can interfere with testing tools, especially near the end of the drive when more extensive reads are performed.

What You Can Do Next

If your Complete Drive Test keeps hanging at 90%, try the following steps:

1. Check SMART Data

Use tools like CrystalDiskInfo or GSmartControl to review the drive’s SMART attributes. Look for:

Reallocated Sector Count

Current Pending Sector Count

Uncorrectable Sector Count

If any of these values are high, the drive is likely failing.

2. Try Another Diagnostic Tool

Use a different brand’s utility (e.g., SeaTools, HD Tune, or HDDScan) to cross-check. Some tools handle bad sectors better or provide more detailed logs.

3. Run CHKDSK with Repair

If the drive is still responsive:

Replace X with your drive letter. This command attempts to locate and repair bad sectors.

4. Back Up Your Data

If you haven't already, back up the drive immediately. A test stalling at 90% is often a sign of impending failure.

5. Consider Drive Replacement

Drives that can’t complete diagnostics shouldn’t be trusted with important data. Check warranty status and initiate an RMA if applicable.

Conclusion

When a Complete Drive Test stops at 90%, it’s often a red flag indicating bad or unreadable sectors, pending mechanical failure, or firmware issues. Don’t ignore it—take it as a warning. Back up your data, run further diagnostics, and consider replacing the drive before total failure occurs.