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Elastic Compute Service:What do I do if .NET Framework 3.5 or a language pack cannot be installed on a Windows instance?

Last Updated:Feb 15, 2025

By default, Windows instances use WSUS (Windows Server Update Services) to obtain updates. This can lead to missing installation files for .NET Framework and language packs, causing errors such as source files not found or language packs not installable. This topic describes solutions for the installation failure of .NET Framework 3.5 or a language pack.

Important
  • This document is applicable to Windows Server 2012 R2 and later versions.

  • For users of the Windows Server 2012 R2 system with the official image installed after June 2023, security patches may prevent the installation of .NET Framework 3.5. For this issue, see Failure to install .NET Framework 3.5 on Windows Server 2012 R2.

  • To continue using the Windows Server 2012 R2 system, you can directly select the Windows Server 2012 R2 images with .NET Framework 3.5 pre-installed (win2012r2_9600_x64_dtc_zh-cn_40G_.Net3.5_alibase_20231204.vhd and win2012r2_9600_x64_dtc_en-us_40G_.Net3.5_alibase_20231204.vhd) from the community images in the ECS console to create an ECS instance. For guidance on locating these images, see Find images.

Problem description

  • Problem 1: An error occurs during the installation of .NET Framework 3.5, as illustrated below.

    找不到源文件

  • Problem 2: Language packs cannot be installed.

    When attempting to switch languages in the Control Panel or searching for language options in Windows Update, language packs are not selectable or installable.

    无法安装语言包

Cause

The default use of WSUS by Windows instances to obtain update sources can result in the absence of synchronized updates containing .NET Framework 3.5 or the corresponding language packs on the WSUS server. Consequently, the Windows instance cannot acquire these updates through WSUS, leading to missing installation files for .NET Framework and language packs, which in turn causes errors such as source files not found or language packs not installable.

Solutions

Solution 1: Install .NET Framework 3.5 using the Cloud Assistant plug-in

  1. Log on to the ECS console.

  2. In the left-side navigation pane, choose Maintenance & Monitoring > Cloud Assistant.

  3. At the top of the left-side navigation pane, select the resource group and region that contain the target resource. Region

  4. On the ECS Instances tab, click Execute Command in the Actions column of the row where the instance resides.

  5. Enter the following content in the command content, and select Execute Now. Due to the large file size, it is recommended to set the Timeout Period to more than 6000 seconds to ensure the download process completes smoothly. Keep other parameters as default, and then click Execute.

    acs-plugin-manager.exe -e -P Windows_RestoreAndUpdate -p "-ByMedia iso -InstallFeature NetFx3"
  6. On the Command Execution Result tab, check the Execution Status of the command.

    When it displays Execution Successful, it indicates that .NET Framework 3.5 has been successfully installed.

Solution 2: Install .NET Framework 3.5 by switching the update source

  1. Switch the update source to Windows Update.

    Switch the update source using PowerShell

    1. Remotely connect to the Windows instance.

      For detailed instructions, see Log on to a Windows instance by using the Workbench tool over the RDP protocol.

    2. Right-click the lower-left corner 开始, and then click Run. In the dialog box, enter powershell, and click OK.

    3. Enter powershell to open the PowerShell interface.

    4. In the PowerShell interface, execute the following command to modify the registry and set the update source to Windows Update.

    Set-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU' -Name UseWUServer -Value 0
    Restart-Service -Name wuauserv

    Switch the update source by configuring group policy

    1. Remotely connect to the Windows instance.

      For detailed instructions, see Log on to a Windows instance by using the Workbench tool over the RDP protocol.

    2. Right-click the lower-left corner 开始, and then click Run. In the dialog box, enter gpedit.msc, and click OK.

    3. Configure the group policy according to the system version.

      • For Windows Server 2012 R2, Windows Server 2016, Windows Server 2019, or Windows Server 2022, follow these steps.

        1. In the Local Group Policy Editor, navigate to Computer Configuration > Administrative Templates > System > Specify Settings For Optional Component Installation And Component Repair. image

        2. Double-click Specify Settings For Optional Component Installation And Component Repair, select Enabled, and then check Download Repair Content And Optional Features Directly From Windows Update Instead Of Windows Server Update Services (WSUS), and click OK. image

      • For Windows Server 2025, perform the following steps.

        1. In the Local Group Policy Editor, navigate to Computer Configuration > Administrative Templates > Windows Components > Windows Update > Manage Updates Offered From Windows Server Update Service > Specify Source Service For Specific Classes Of Windows Updates.

        2. Double-click Specify Source Service For Specific Classes Of Windows Updates, select Enabled, set Feature Updates to Windows Update, and then click OK. image

    4. Right-click the lower-left corner 开始, and then click Run. In the dialog box, enter gpupdate /force, and click OK to force the update of the local group policy.

  2. Install .NET Framework 3.5.

    Note

    The memory usage of the Windows Server 2012 or Windows Server 2016 operating system is high. If you install other applications, memory usage may continue to increase, potentially causing insufficient memory and a failure to install .NET Framework. To prevent this, consider adding physical memory. If the instance is I/O optimized, it has a higher disk I/O capability and can complete data exchange faster than a regular instance when processing virtual memory read and write operations, thereby reducing the impact on system performance. For instructions on configuring virtual memory for Windows instances, see How to configure virtual memory for Windows instances.

    Install using the Server Manager UI

    1. Click the lower-left corner 开始, and click Server Manager.

    2. In Server Manager, click Add Roles And Features.

    3. Proceed with the wizard using default configurations, and select .NET Framework 3.5 Features in the Features section.

      image

      Continue with the wizard to confirm the settings and complete the installation.

      image

    Install by executing PowerShell commands

    Execute one of the following commands:

    • Dism /Online /Enable-Feature /FeatureName:NetFX3 /All 

      image.png

    • Install-WindowsFeature -Name NET-Framework-Features

      image.png

    Important

    If the installation of .NET Framework reports errors such as 0x800F0906 or 0x800F081F, as shown below, refer to .NET Framework 3.5 installation errors for solutions.

    image

  3. (Conditionally required) If your Windows environment relies on WSUS for updates, execute the following commands to configure WSUS as the update source.

    Set-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU' -Name UseWUServer -Value 1
    Restart-Service -Name wuauserv

References