INTRODUCTION

WHAT IS MICROSOFT .NET FRAMEWORK 3.5?

Microsoft .NET Framework 3.5 is a common prerequisite for legacy applications and a general guideline is to install it. This post is a guide for how to install .NET Framework 3.5 on Windows Server 2012, Windows Server 2016 and Windows 10.

First available on January 16, 2008, the Microsoft .NET Framework 3.5 is a framework with a shared library of code that can be used by developers. It also provides a run-time environment for applications.

HOW DO I KNOW WHICH VERSIONS OF .NET FRAMEWORK I HAVE INSTALLED?

There are several ways of checking which .NET Framework versions you have installed:

  • Control Panel
  • Registry
  • Powershell

For more information refer to this article:
https://docs.microsoft.com/en-us/dotnet/framework/migration-guide/how-to-determine-which-versions-are-installed#ps_a

HOW DO I INSTALL IT?

This blog post describes how to install .NET Framework 3.5 using:

  1. Command line (DISM)
  2. Powershell
  3. Server Manager (GUI)
  4. Offline Installer

Unfortunately, installing Microsoft .NET Framework 3.5 is not as straight forward as you might think. Microsoft has a guide for installing .NET Framework 3.5, but it does not provide the full story.

If you are trying to install the feature from Server Manager or from Programs and Features, you will see this error during installation:

“Do you want to specify an alternate source path? One or more installation selections are missing source files…”

Bug when adding .net framework 3.5 in Server 2012

SOLUTION

You can use any of the below solutions to solve the issue with installing .NET Framework 3.5.

COMMAND LINE

Go to a command prompt and enter this command:

dism /online /enable-feature /featurename:NetFX3 /all /Source:d:\sources\sxs /LimitAccess

Note: Source should be the Windows installation disc. In my case, this was located on D:

Bug when adding .net framework 3.5 in Server 2012

POWERSHELL

It is also possible to install .NET Framework 3.5 using Powershell. Use this command to accomplish this:

Add-WindowsCapability –Online -Name NetFx3~~~~ –Source D:\sources\sxs

ADD ROLES AND FEATURES WIZARD

Go down to Specify an alternate source path and enter <media drive>:\sources\sxs as the path.

Enter the source path. This should be the Windows media path.

Specify alternate source path windows server 2012 .net framework 3.5

INSTALL USING OFFLINE INSTALLER: 

You can also install .NET Framework 3.5 using the Offline Installer: https://www.microsoft.com/en-us/download/confirmation.aspx?id=25150

REVIEW INSTALLATION

Once you have followed one of the above 3 installation methods, you should see the .NET Framework 3.5 Feature installed. You can verify this via:

  1. The GUI
  2. Powershell

THE GUI

.NET Framework 3.5 feature installed on Windows Server 2012

POWERSHELL

Use the below Powershell command to see if .NET Framework 3.5 has been installed and with which subversions:

(Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5").Version

REFERENCES

Microsoft Docs – Install .NET Framework 3.5

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