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    File Storage NAS:Mount an SMB file system

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    File Storage NAS:Mount an SMB file system

    Last Updated:Dec 25, 2025

    Mount a NAS file system that uses the Server Message Block (SMB) protocol on a Windows server to share files. This topic describes how to mount an SMB file system on an Alibaba Cloud Elastic Compute Service (ECS) instance that runs Windows.

    Prerequisites

    • You have created an ECS instance that runs Windows. For more information, see Create an ECS instance.

    • You have created an SMB file system on NAS and obtained its mount target address. The file system and the ECS instance must be in the same region and Virtual Private Cloud (VPC). For more information, see Create a General-purpose NAS file system in the console.

    • Network connectivity is established.

      • If you are mounting over a classic network, the ECS instance and the NAS file system must belong to the same Alibaba Cloud account.

      • The file system's permission group must grant access to the Windows ECS instance.

      • TCP port 445 must be open, as it is required for SMB communication.

        If port 445 is not open, add a rule to the security group of the target ECS instance to allow traffic on this port. For more information, see Add a security group rule.

    Step 1: Prepare the environment

    Perform these steps once on each Windows server before you mount a file system for the first time.

    Note

    1. Connect to the ECS instance.

    2. On the following Windows versions, you need to allow insecure guest logons.

      1. For Windows Server 2016 and later, run the following command.

        REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\LanmanWorkstation\Parameters /f /v AllowInsecureGuestAuth /t REG_DWORD /d 1

      2. For Windows Server 2025, you also need to disable SMB signing. Use one of the following methods:

        • Method 1: Use Group Policy (GUI)

          1. Press Win+R and enter gpedit.msc to open the Local Group Policy Editor.

          2. Navigate to Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options. Double-click Microsoft network client: Digitally sign communications (always), select Disabled, and then click OK.image

        • Method 2: Use the registry

          If you cannot use Group Policy, disable SMB signing by using the registry. Choose one of the following methods:

          Registry Editor

          1. Press Win+R and enter regedit to open the Registry Editor.

          2. Navigate to the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters.

          3. Find the RequireSecuritySignature entry and set its value to 0.

          4. Restart the computer for the change to take effect.

          Command line

          1. Open Command Prompt as an administrator and run the following command:

            reg add "HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters" /v RequireSecuritySignature /t REG_DWORD /d 0 /f

          2. Restart the computer for the change to take effect.

    3. Enable the Workstation service.

      1. Navigate to All Programs > Accessories > Run, or press Win+R and enter services.msc to open the Services console.

      2. In the list of services, find Workstation. Verify that its status is Started and its startup type is Automatic.

        By default, the Workstation service is running.

        Workstation

    4. Enable the TCP/IP NetBIOS Helper service.

      1. Open the Network and Sharing Center and click the active network connection.

      2. Click Properties, double-click Internet Protocol Version 4 (TCP/IPv4), and then click Advanced.

      3. In the Advanced TCP/IP Settings dialog box, click the WINS tab and select Enable NetBIOS over TCP/IP.Enable NetBIOS over TCP/IP

      4. Navigate to All Programs > Accessories > Run, or press Win+R and enter services.msc to open the Services console.

      5. In the list of services, find TCP/IP NetBIOS Helper. Verify that its status is Started and its startup type is Automatic.

        By default, the TCP/IP NetBIOS Helper service is running.

        TCP/IP NetBIOS Helper

    Step 2: Mount the SMB file system

    Mount an SMB file system manually for temporary access or configure an automatic mount that persists after server restarts. We recommend configuring an automatic mount after a successful manual mount.

    Manually mount the file system

    Mount the NAS SMB file system on your Windows ECS instance by using its mount target address.

    1. Connect to the ECS instance.

    2. Open a Command Prompt window and run the following command to mount the SMB file system.

      net use Z: \\file-system-id.region.nas.aliyuncs.com\myshare

      Parameter

      Description

      Z

      The drive letter for the mapped file system. Choose an unused letter, especially if you plan to mount multiple file systems.

      file-system-id.region.nas.aliyuncs.com

      The mount target address that was generated when you created the SMB file system. Replace this placeholder with your actual address.

      In the NAS console, click the file system ID, go to the Mount Targets tab, and then hover over the Mount Target icon in the Mount Target column to find the address.

      myshare

      The name of the SMB share. Do not change this value.

      For Windows Server 2019 and later, use the New-SmbGlobalMapping PowerShell cmdlet to ensure that the mount point is accessible to all users. The commands are as follows:

      If you are prompted for credentials, enter any valid credentials for the workgroup. For example, use workgroup\administrator and the password for the ECS administrator account.

      • Mount command

        New-SmbGlobalMapping -LocalPath z: -RemotePath \\file-system-id.region.nas.aliyuncs.com\myshare -Persistent $true

      • Unmount command

        Remove-SmbGlobalMapping -LocalPath z:

      • Verify mount commandGet-SmbGlobalMapping

    3. Verify that the SMB file system is mounted successfully.

      • Run the following command:

        net use

      • Example output

        A similar output confirms a successful mount. You can now read from and write to the NAS file system on your ECS instance.

        Check mount result

      If the mount fails, use a script to automatically diagnose the issue or refer to common error codes for solutions. For more information, see Run the auto-check script to troubleshoot the failure of mounting an SMB file system on Windows and FAQ about mounting.

    Optional: Automatically mount the file system

    To automatically mount the SMB file system when the ECS instance restarts, create a startup script in the following location:

    c:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp\auto_mount.bat

    1. Open a Command Prompt window and run the following command to create the auto_mount.bat script.

      echo %HOMEPATH%\mount.bat > auto_mount.bat

    2. Run the following three commands to move the script to the startup folder, grant read and execute permissions to all users, and register the script to run at startup.

      MOVE auto_mount.bat "c:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp"
      icacls "c:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp\auto_mount.bat" /grant everyone:rx
      REG ADD HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run /f /v MyMount /t REG_SZ /d "c:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp\auto_mount.bat"

    3. Run the following command to create the mount.bat script.

      Mount without authentication

      For scenarios that do not require authentication, use the following command:

      echo net use z: \\file-system-id.region.nas.aliyuncs.com\myshare > "%HOMEPATH%\mount.bat"

      Mount with authentication

      If your SMB file system uses Active Directory (AD) or ACLs and you need to mount it with domain credentials different from the current user, run the following command to configure the script.

      echo net use z: \\file-system-id.region.nas.aliyuncs.com\myshare /user:user@domain password > "%HOMEPATH%\mount.bat"

      Replace the drive letter z, mount target address file-system-id.region.nas.aliyuncs.com, domain username user@domain, and domain user password password with your actual values.

    4. Restart the ECS instance.

      After the instance restarts and you log back in, run the net use command to verify the mount.

      Important

      Restarting the ECS instance interrupts your services. Perform this operation during off-peak hours.

    References