Encountering Windows System Error Code ERROR_66 can be frustrating, especially when you’re unsure what it means or how to resolve it. This error typically indicates a problem with accessing certain system resources, often related to file sharing or network permissions. Don’t worry — in this detailed, easy-to-follow troubleshooting guide, we’ll walk you through fixing ERROR_66 step-by-step so you can get your system back to smooth operation.
What is Windows System Error Code ERROR_66?
Before diving into the fixes, let’s quickly understand what ERROR_66 means. In Windows, Error Code 66 usually refers to:
"The network resource type is not correct."
This often shows up when your system is trying to map a network drive, access shared network resources, or run scripts related to networked files.
Step 1: Confirm the Exact Error Message and Context
The first step to fixing any Windows error is to understand the context:
- When does ERROR_66 appear? During startup, when running a program, or when mapping a network drive?
- Note the full error message that appears.
- Jot down any relevant filenames, network shares, or drive letters mentioned.
Understanding where and how the error occurs will help you avoid blind fixes and target the root cause.
Step 2: Check Network Resource Type and Accessibility
ERROR_66 often means Windows is trying to access an incorrect or unavailable network resource type. Here’s what to do:
1. Verify Network Path
- Make sure the network path is correctly typed. For example,
\\servername\sharenameshould be exact. - If the network share name has changed, update the reference in your scripts, shortcuts, or mapped drives.
2. Test Network Connectivity
-
Open Command Prompt and ping the server:
sh
ping servername - If the ping fails, fix your network connection or DNS settings before proceeding.
3. Confirm Resource Sharing Settings
- On the host machine (server or PC sharing the resource), check:
- The folder is actually shared.
- You have appropriate permissions (read, write).
- On your PC, ensure you’re using correct credentials, especially if the share requires authentication.
Step 3: Correct Drive Mapping Issues
If the error occurs during drive mapping, follow these steps:
1. Remove Existing Mapped Drive
Sometimes stale or invalid mapping causes ERROR_66.
- Open File Explorer.
- Right-click the mapped drive showing errors and select Disconnect.
Alternatively, in Command Prompt, type:
sh
net use Z: /delete
(Replace Z: with your actual drive letter.)
2. Remap the Drive
- Click This PC > Computer tab > Map network drive.
- Enter the correct network folder path.
- Check Reconnect at sign-in if you want permanent mapping.
- Enter network credentials if prompted.
Step 4: Run Windows Network Troubleshooter
Windows has a built-in troubleshooter designed to diagnose and fix network resource issues.
- Go to Settings > Update & Security > Troubleshoot > Additional troubleshooters.
- Select Network Adapter and run the troubleshooter.
- Follow on-screen instructions and apply recommended fixes.
This could patch common underlying problems quickly.
Step 5: Check Firewall and Security Software Settings
Sometimes, firewall or antivirus software blocks network resources, triggering ERROR_66.
- Temporarily disable third-party antivirus or firewall software.
- Check if the error persists.
- If disabling resolves the error, create exceptions or rules in your security software to allow access to the network resources you need.
- Don’t forget to re-enable security software after testing.
Step 6: Verify System File Integrity
Corrupted system files can also cause network errors.
- Open Command Prompt as Administrator.
-
Run the System File Checker:
sh
sfc /scannow - Wait until the scan completes. It will automatically repair any detected issues.
- Restart your PC and check whether ERROR_66 is resolved.
Step 7: Update Network Drivers
Outdated or corrupt network adapter drivers can cause connectivity errors.
- Press Windows + X, select Device Manager.
- Expand Network adapters.
- Right-click your adapter and choose Update driver.
- Select Search automatically for updated driver software.
- Restart your system after updates.
Step 8: Review Group Policy and Registry Settings (Advanced)
If you’re on a corporate or domain network, Group Policy misconfigurations can cause network errors.
- Contact your IT admin if necessary.
- Check for policies restricting network drives or share access.
- Registry settings related to network shares should only be edited if you are confident — backup the registry first.
Bonus Tips: Prevent ERROR_66 in the Future
- Always keep your Windows OS and drivers updated.
- Regularly verify that shared resources exist and have correct permissions.
- Use reliable network storage devices that maintain consistent naming conventions.
- Avoid hardcoding network paths in scripts; consider environment variables or UNC paths.
Final Thoughts
Windows System Error Code ERROR_66 might sound intimidating, but with a methodical approach and some patience, it’s one you can tackle confidently. We hope this guide helped you understand why the error happens and how to fix it yourself.
If you continue facing problems or the error is linked to complex domain/network setups, don’t hesitate to seek professional IT assistance.
If you found this guide useful, feel free to share it with others struggling with ERROR_66 — your support helps others fix their Windows frustrations quickly!
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If you want me to create a printable PDF or a quick checklist summarizing these steps, just let me know!
