When there is a hard drive or partition issue in Windows, a warning stating, "a disk read error occurred" may appear. This message is likely followed with instructions to pressCtrl+Alt+Delto restart, which you should do to see if the problem is resolved. However, if the computer reboots only to display the same error message, troubleshooting the issue is required.

These instructions apply to Windows 10, Windows 8, and Windows 7.

How to Fix It When A Disk Read Error Occurs

While it may seem like looking at the hard drive first would be the best solution, there are several other potential fixes for disk read errors. Walking through potential fixes for frequent reasons for this error could pinpoint and resolve the issue.

1. Run a desktop clean up utility. This removes any files that could cause a memory error. Although, the errant file could be a symptom of more serious issues, cleaning up the desktop is good for maintenance.

2. Defrag the computer. In certain circumstances, this could fix the issue. You may have to connect the HDD to another machine to perform the defragmentation and then boot from it.

3. Test the RAM. A problem when booting could be the result of problems with the computer's memory. You can use Windows Memory Diagnostic by enteringmdschedinto theWindows Search(or Start Search) box and pressingEnter. The tool runs automatically when you restart the computer. Alternatively, there are several free memory test programs you could try.

4. Check the cables. Loose connections or faulty cables can cause issues with booting as well as hard drive errors. Look for disconnected cables. If possible, swap out the cables with spares. At the very least, disconnect them, inspect the cables for any damage, then reseat them securely.

5. Test the hard drive. This could mean removing the hard drive from your current machine and plugging it into a working computer, where you can scan for bad sectors. This could help determine whether the issue is repairable or if you need a new hard disk drive (HDD) and a fresh install of Windows.

6. Reset the BIOS. Reverting the BIOS to defaults could resolve the issue. Access the BIOS at startup and look for an option to load BIOS setup defaults, which could be one of the following or similar:

   • Load BIOS Defaults
   • Load Default Settings
   • Load Fail-Safe Defaults

   Alternatively, update the BIOS version to the latest available.

7. Reseat the computer's RAM. Due to heat, the RAM can wiggle its way partially out of the slot, triggering a memory error.

8. Replace the RAM. Or, if there are two RAM modules in the system, interchange their slots.

9. Rebuild the boot sector. When you are unable to start the computer and see a disk read error, the boot configuration data store (BCD) could be corrupt, missing, or incorrectly configured. In addition, use the Bootrec.exe tool to troubleshoot other startup issues. For instance, the fixmbr command allows the repair of a corrupted or damaged Master Boot Record, and the fixboot command writes a new partition boot sector.

10. Rescue data. In some cases, a severely corrupted or failing hard drive might need to be replaced. If this is the case, you could recover files, even if the computer doesn't start. Although it might take some effort, using a data recovery program could save important files.

Causes of Disk Read Errors

Although the origin of this error can vary from one computer to the next, there are some common causes, including the following:

• Insufficient RAM.
• Loose or faulty connections.
• A damaged hard drive.
• A damaged boot configuration data store (boot sector).