By default, Windows Elastic Compute Service (ECS) instances use Windows Server Update Services (WSUS) to obtain updates. This may cause .NET Framework and language pack installation files to be missing. As a result, the system fails to find the installation files or install the language packs. This topic describes how to resolve the issue that you cannot install .NET Framework 3.5 or a language pack.
This topic applies to Windows Server 2012 R2 and later versions.
If your instance runs Windows Server 2012 R2 and uses an official Windows image released after June 2023, you cannot install .NET Framework 3.5 in the operating system because the image includes a specific security patch. For information about the solution to this issue, see the Windows Server 2012 R2: .NET Framework 3.5 fails to be installed section of the "Known issues of public images" topic.
If you want to use the Windows Server 2012 R2 operating system, we recommend that you create ECS instances in the ECS console by using one of the following Windows Server 2012 R2 community images on which .NET Framework 3.5 is 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. For information about how to find the image that you need, see Find an image.
Problem description
Issue 1: When you install .NET Framework 3.5 on a Windows instance, an error message appears, as shown in the following figure.
Issue 2: A language pack cannot be installed on a Windows instance.
When you change the language in Control Panel or search for a language in the Windows Update window, you cannot select or install the language pack that you want.
Cause
The Windows instance uses WSUS as the update source. However, the WSUS server does not provide updates for .NET Framework 3.5 or language packs. The Windows instance cannot obtain the corresponding updates from the WSUS server. As a result, the preceding issues occur because the installation files of .NET Framework and language packs do not exist on the instance.
Solutions
Solution 1: Install .NET Framework 3.5 by using the Cloud Assistant plug-in
Log on to the ECS console.
In the left-side navigation pane, choose .
In the top navigation bar, select the region and resource group to which the resource that you want to manage belongs.
On the ECS Instances tab, find the ECS instance that you want to manage and click Run Command in the Actions column.
In the Command content section, enter the following content and select Immediate execution in the Execution Plan section. If the file that you want to download is large, we recommend that you set the Timeout parameter to more than 6000 seconds. Retain the default settings for other parameters and click Run.
acs-plugin-manager.exe -e -P Windows_RestoreAndUpdate -p "-ByMedia iso -InstallFeature NetFx3"You can view the Execution Status column that corresponds to the command on the Command Execution Result tab.
If Successful is displayed, .NET Framework 3.5 is installed.
Solution 2: Change the update source to install .NET Framework 3.5
Change the update source to Windows Update.
Use PowerShell
Connect to the Windows ECS instance that you want to manage.
For more information, see Use Workbench to connect to a Windows instance over RDP.
In the lower-left corner of the desktop, right-click the
icon and select Run. In the Run dialog box, enter powershelland click OK.Enter
powershell.On the PowerShell interactive interface, run the following commands to configure Windows Update as the update source in the registry:
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU' -Name UseWUServer -Value 0 Restart-Service -Name wuauservConfigure a group policy
Connect to the Windows ECS instance that you want to manage.
For more information, see Use Workbench to connect to a Windows instance over RDP.
In the lower-left corner of the desktop, right-click the
icon and select Run. In the Run dialog box, enter gpedit.mscand click OK.Configure a group policy based on the actual operating system version.
If the instance runs Windows Server 2012 R2, Windows Server 2016, Windows Server 2019, or Windows Server 2022, perform the following steps:
In the Local Group Policy Editor window, choose .
Double-click Specify settings for optional component installation and component repair, select Enabled, select Download fixes and optional features directly from Windows Update instead of Windows Server Update Services (WSUS), and then click OK.
If the instance runs Windows Server 2025, perform the following steps:
In the Local Group Policy Editor window, choose .
Double-click Specify source service for specific classes of Windows Updates, select Enabled, set Feature Updates to Windows Update, and then click OK.
In the lower-left corner of the desktop, right-click the
icon and select Run. In the Run dialog box, enter gpupdate /forceand click OK to forcefully update the local group policies.
Install .NET Framework 3.5.
NoteThe Windows Server 2012 or Windows Server 2016 operating system has high memory usage. If you install other applications in the operating system, memory usage continues to increase and memory becomes insufficient, which may cause a failure to install .NET Framework. To prevent the issue, we recommend that you increase physical memory. If an I/O optimized instance is used to provide high disk I/O performance, the instance reads data from and writes data to virtual memory faster than non-I/O optimized instances. We recommend that you specify the Windows virtual memory for the I/O optimized instance. For more information, see How do I configure the virtual memory of a Windows instance?
Use Server Manager
In the lower-left corner of the desktop, click the
icon and then click Server Manager.In the Server Manager window, click Add roles and features.
Follow the default wizard configurations. In the Features step, select .NET Framework 3.5 Features.
Follow the wizard to confirm the settings until the installation is complete.
Run a PowerShell command
Run one of the following commands:
Dism /Online /Enable-Feature /FeatureName:NetFX3 /All
Install-WindowsFeature -Name NET-Framework-Features
ImportantIf the system reports an error, such as
0x800F0906or0x800F081F, as shown in the following figure, fix the error. For information about how to fix the error, see .NET Framework 3.5 installation errors: 0x800F0906, 0x800F081F, 0x800F0907, 0x800F0922.
(Conditionally required) If your Windows environment requires WSUS-based updates, run 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
.NET Framework 3.5 is a software development framework provided by Microsoft. It contains the core class libraries and runtime environments that are required for developing and running .NET Framework-based applications. The language packs of .NET Framework 3.5 are add-ons compatible with the framework to support multiple languages. For more information, see Overview of .NET Framework.
For information about how to install a version of .NET Framework in other Windows Server versions, see Installation guide.
For information about how to install .NET Framework 3.5 or .NET Framework 4.x in Windows Server 2016 or later, see Install .NET Framework on Windows Server 2016 or later.
For information about how to install .NET Framework 3.5 or .NET Framework 4.x in Windows Server 2022, see Install .NET Framework on Windows Server 2022.