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How to Fix Windows System Error Code ERROR_40: A Step-by-Step Guide


Encountering an error code on your Windows PC can be frustrating, especially when it interrupts your workflow or gaming experience. One such error is System Error Code ERROR_40, which can appear out of the blue and leave you uncertain about what went wrong or how to resolve it. The good news? You don’t need to be a tech wizard to fix it. In this detailed, step-by-step guide, we will walk you through troubleshooting and resolving ERROR_40 effectively.


What is Windows System Error Code ERROR_40?

Before diving into the fix, it’s helpful to understand what ERROR_40 means. In Windows, ERROR_40 typically refers to "The request is not supported." This error occurs when a program or process attempts an operation that the system or device driver does not support. It can happen due to incompatible drivers, corrupt system files, or certain network or hardware misconfigurations.


Common Causes of ERROR_40

  1. Outdated or corrupt device drivers
  2. Corrupted system files or registry entries
  3. Unsupported hardware interactions
  4. Network adapter or protocol conflicts
  5. Third-party software conflicts or malware

Knowing this helps guide our troubleshooting steps.


Step-by-Step Guide to Fix ERROR_40 on Windows

Step 1: Restart Your Computer

Sometimes a simple restart is all you need. This clears temporary glitches that may cause ERROR_40.

  • Save your work.
  • Click the Start menu → PowerRestart.

Check if the error persists after reboot.


Step 2: Run Windows Update

Keeping Windows updated fixes bugs and keeps drivers current.

  1. Click StartSettings (gear icon).
  2. Select Update & Security.
  3. Click Windows UpdateCheck for updates.
  4. Download and install any updates, then restart your PC.


Step 3: Update Device Drivers

Outdated or corrupt drivers are a very common cause of ERROR_40.

  1. Press Windows + X, then select Device Manager.
  2. Identify devices showing warning signs (yellow exclamation marks).
  3. Right-click the device → Update driverSearch automatically for updated driver software.
  4. Follow prompts; if no updates are found, visit the device manufacturer’s website for the latest drivers.
  5. Restart your PC.


Step 4: Run System File Checker (SFC)

Corrupt or missing system files can throw errors like ERROR_40.

  1. Press Windows + S, type cmd.
  2. Right-click Command PromptRun as administrator.
  3. Type the following and press Enter:

    sfc /scannow

  4. Wait for the scan to complete. It will attempt to repair any corrupted files automatically.
  5. Restart your PC and check if the error is resolved.


Step 5: Use DISM Tool to Repair Windows Image

If SFC doesn’t resolve the issue, use DISM (Deployment Image Servicing and Management).

  1. Open Command Prompt as an administrator.
  2. Run these commands one by one:

    DISM /Online /Cleanup-Image /ScanHealth
    DISM /Online /Cleanup-Image /RestoreHealth

  3. After completion, restart your PC.


If ERROR_40 appears related to network actions:

  1. Go to Device Manager → expand Network adapters.
  2. Right-click your adapter → Uninstall device.
  3. Restart your computer; Windows will reinstall the driver.
  4. Alternatively, right-click the adapter → PropertiesAdvanced settings. Reset to default or disable problematic features.


Step 7: Scan for Malware and Run Antivirus

Sometimes malware causes unexpected errors.

  • Use Windows Defender or your trusted antivirus software.
  • Perform a full system scan.
  • Quarantine or remove any threats detected.
  • Restart the system.


Step 8: Perform a Clean Boot

Third-party software conflicts might cause ERROR_40.

  1. Press Windows + R, type msconfig → Enter.
  2. In the System Configuration window, go to the Services tab.
  3. Check Hide all Microsoft services.
  4. Click Disable all.
  5. Go to the Startup tab, then click Open Task Manager.
  6. Disable all startup items.
  7. Close Task Manager and click OK in System Configuration.
  8. Restart PC and see if the error persists.

If fixed, enable services/startups one by one to find the culprit.


Step 9: Restore Your System to an Earlier Point

If the problem started recently, a system restore might help.

  1. Type Create a restore point in the taskbar search and select it.
  2. Click System Restore.
  3. Choose a restore point before the error appeared.
  4. Follow the on-screen instructions.


Step 10: Seek Professional Help or Reinstall Windows

If none of the above work, the issue might be deeper or hardware-related.

  • Consult a professional technician or contact Microsoft Support.
  • As a last resort, back up your data and perform a clean Windows installation.


Final Thoughts

ERROR_40 is a manageable Windows error that often resolves with simple steps like driver updates or system scans. Follow this guide patiently, and you’ll likely have your system running smoothly again in no time.


Bonus Tips for Avoiding Such Errors

  • Always keep your system and drivers up to date.
  • Avoid installing suspicious or unverified software.
  • Back up your system regularly.
  • Run malware scans frequently to stay protected.


If you found this guide helpful, share it with friends or colleagues facing the same issue! If you have questions or want to share your success story, drop a comment below.


Keywords: Windows System Error Code ERROR_40, Fix ERROR_40, ERROR_40 Windows troubleshooting, Windows error code, system error fix, driver update Windows, SFC scan Windows, DISM repair Windows.


By taking these steps, you’re empowering yourself to handle technical glitches confidently. Happy computing!

Updated on June 17, 2025
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