Accessing Windows network shares (SMB) is a daily task for most IT professionals, but it can be a source of major frustration when it fails. Cryptic error messages like “Access is Denied” or “The network path was not found” can stop an automation script in its tracks.

I’ve found that these errors almost always fall into one of three categories: Connectivity, Permissions, or Security Policy. This guide provides a systematic, step-by-step process to diagnose and solve the most common SMB errors, saving you from hours of frustration.

The Diagnostic Flow: A Systematic Approach

Instead of guessing, follow this logical flow. Start at the top and move down until your issue is resolved.

  1. Test Connectivity (Port 445): Can your client machine reach the server on the correct port? 

    Test-NetConnection -ComputerName "YourServerName" -Port 445
    If TcpTestSucceeded is False, you have a Connectivity Problem. Go to Part 1.

  2. Test Guest/Anonymous Access: If connectivity is confirmed, can you list the shares anonymously? 

    net view \\YourServerName
    If you get "System Error 5 has occurred. Access is denied.", you have a Permissions Problem. Go to Part 2.

  3. Test Secure Connection: If the previous steps work but your application still fails, you may have a security policy mismatch. If the error mentions SMB Signing, you have a Security Policy Problem. Go to Part 3.

Part 1: Fixing Connectivity - “The network path was not found” (Error 53)

This error means your computer cannot find a route to the server. It’s a fundamental networking issue.

Root Cause: Name Resolution or Firewall

  1. Name Resolution Failure: Your computer cannot resolve the server’s hostname to an IP address.
  2. Network Path Blocked: A firewall on the client, server, or network is blocking the SMB port (TCP 445).

The Solution: A Step-by-Step Diagnostic Process

I follow these steps on the client machine to diagnose and fix the problem.

Step 1: Fix Name Resolution

If Test-NetConnection failed, try it again with the server’s IP address. 

Test-NetConnection -ComputerName "192.168.1.10" -Port 445
If this succeeds, your problem is DNS or name resolution. For a permanent fix, add an entry to your client’s hosts file (C:\Windows\System32\drivers\etc\hosts) mapping the IP to the hostname. 
192.168.1.10    YourServerName

Step 2: Ensure the SMB Port (445) is Open

If Test-NetConnection fails even with the IP address, a firewall is likely blocking the port.

On the Server: Run these PowerShell commands as an Administrator to ensure the firewall allows SMB traffic. 

# Enable the built-in "File and Printer Sharing" firewall group
Enable-NetFirewallRule -DisplayGroup "File and Printer Sharing"
# Ensure the SMB server service is running
Start-Service LanmanServer
Set-Service LanmanServer -StartupType Automatic

By fixing connectivity and name resolution, you eliminate Error 53.

Part 2: Fixing Permissions - “Access is Denied” (Error 5)

This error means you’ve reached the server, but it has rejected you. When accessing a share that should be “open,” the cause is almost always a server-side policy blocking guest access.

Root Cause: Blocked Guest/Anonymous Access

Modern Windows versions, for security, disable insecure guest logons by default. Even if your share permissions allow “Everyone,” this policy will reject any connection that isn’t explicitly authenticated with a known user account.

The Solution: Enable Insecure Guest Logons on the Server

To resolve this for a trusted internal network, you must change this policy on the server hosting the share.

Run the following in an elevated PowerShell prompt on the server: 

# Allow insecure guest logons, required for guest access to SMB shares
Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters" `
    -Name "AllowInsecureGuestAuth" -Value 1 -Type DWord -Force

# Restart the SMB server service to apply the changes
Restart-Service -Name "LanmanServer" -Force

Write-Host "✅ Guest access enabled. You can now test the connection from a client." -ForegroundColor Green

Security Warning: This setting should only be used in trusted, internal networks. For any sensitive environment, always use shares secured with specific, authenticated user accounts.

Part 3: Fixing Policy - “SMB Signing Required”

If you can connect but receive an error stating “your computer is configured to require SMB signing,” you have a security policy mismatch.

Root Cause: SMB Signing Mismatch

SMB signing is a feature that verifies the integrity of every packet to prevent man-in-the-middle attacks. The error occurs when your client requires signing, but the server does not. The client, enforcing its stricter policy, refuses to connect.

The Solution: Align SMB Signing Policies

You must make the client and server agree.

Option A: Disable Signing Requirement on the Client (Quick Fix)

This is the fastest solution for trusted networks. Run this in an elevated PowerShell prompt on the client: 

# Disable the requirement for SMB signing on the client
Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters" `
    -Name "RequireSecuritySignature" -Value 0 -Type DWord -Force

Write-Host "SMB signing requirement has been disabled on this client." -ForegroundColor Green
The change is immediate.

Option B: Enable SMB Signing on the Server (More Secure)

For production environments, the better fix is to enforce signing on the server. Run this in an elevated PowerShell prompt on the server: 

# Enable and require SMB signing on the SERVER
Set-SmbServerConfiguration -RequireSecuritySignature $true -Force

Write-Host "SMB signing has been enabled and required on this server." -ForegroundColor Green

Conclusion

Troubleshooting SMB errors is a logical process, not guesswork. By following the diagnostic flow—Connectivity -> Permissions -> Policy—you can systematically identify and resolve the most common issues that block network share access.

  1. First, ensure you can reach the server on port 445 to fix Error 53.
  2. Next, ensure the server allows guest logons to fix Error 5.
  3. Finally, ensure both client and server agree on SMB signing policies.

Keeping this framework in mind will turn a frustrating dead-end into a solvable, step-by-step puzzle.