When accessing Samba shares from Windows 7, the system caches authentication credentials by default. This becomes problematic in shared workstation environments where multiple users might access the same machine. The cached credentials allow subsequent access without re-authentication, creating potential security vulnerabilities.

Windows stores SMB/CIFS credentials in two primary locations:

• Credential Manager (GUI accessible)
• Protected storage subsystem (registry-based)

For Samba workgroup configurations (non-domain), Windows typically stores these in the Windows Vault.

Here are three effective ways to clear Samba authentication credentials:

1. Using Command Line

The most efficient method is through the Windows command prompt:

net use * /delete /y

This command will:

• Delete all active SMB connections
• Clear cached credentials for network shares
• Force re-authentication on next access attempt

2. Via Credential Manager

For GUI-based clearance:

1. Open Control Panel > User Accounts > Credential Manager
2. Select "Windows Credentials"
3. Locate entries under "Generic Credentials" for your Samba server
4. Click "Remove" for each relevant entry

3. Registry Cleanup (Advanced)

For stubborn credentials that persist:

reg delete "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones" /f

Warning: Registry edits should be performed carefully with proper backups.

For system administrators needing to automate this process across multiple machines, consider this PowerShell script:

# Clear SMB connections
Get-SmbMapping | Remove-SmbMapping -Force

# Clear credential cache
cmdkey /list | ForEach-Object {
    if($_ -like "*target=*" -and $_ -like "*samba*") {
        $target = $_ -replace ".*target=",""
        cmdkey /delete:$target
    }
}

# Clear DNS cache for good measure
Clear-DnsClientCache

To configure Windows 7 to not cache Samba credentials:

reg add "HKLM\SYSTEM\CurrentControlSet\Control\Lsa" /v DisableDomainCreds /t REG_DWORD /d 1 /f

Or through Group Policy:

1. Open gpedit.msc
2. Navigate to: Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options
3. Set "Network access: Do not allow storage of passwords and credentials for network authentication" to Enabled

If cleared credentials still allow access, check:

• Recycle Bin for credential backups
• Stored credentials in web browsers
• Mapped drives that might re-authenticate

On the Samba side, you can enforce session timeouts by adding to smb.conf:

[global]
    # Force re-authentication every 30 minutes
    kernel oplocks = no
    oplocks = no
    strict locking = yes
    deadtime = 30

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When accessing Samba shares from Windows 7, the operating system silently caches your authentication credentials. While convenient for regular use, this becomes a security concern when you need to ensure credentials don't remain on a shared workstation. The issue is particularly acute in workgroup environments where domain-level credential management isn't available.

The most effective way to purge these cached credentials is using the net use command:

net use * /delete /y

This command performs three critical actions:

• Terminates all active SMB connections
• Clears cached credentials for network resources
• The /y flag suppresses confirmation prompts

For more surgical removal when you have multiple connections:

net use \\sambaserver\sharename /delete

Where \\sambaserver\sharename should be replaced with your actual Samba server and share path.

For GUI-oriented users:

1. Open Control Panel → User Accounts → Credential Manager
2. Navigate to "Windows Credentials"
3. Locate entries under "Generic Credentials" for your Samba server
4. Click "Remove" for each relevant entry

For frequent users, create a batch script (clear_smb.bat):

@echo off
echo Clearing SMB credentials...
net use * /delete /y >nul 2>&1
if errorlevel 1 (
    echo Failed to clear credentials
    exit /b 1
)
echo Credentials cleared successfully

To stop Windows from caching credentials in the first place:

reg add "HKLM\SYSTEM\CurrentControlSet\Control\Lsa" /v DisableDomainCreds /t REG_DWORD /d 1 /f

Note: This registry change affects all network credentials and may impact other network operations.

After running clearance commands, verify with:

net use

This should return "There are no entries in the list" when successful.