Installing the .NET Framework 4.5, 4.5.1

This article provides links for installing the .NET Framework 4.5 and 4.5.1 on your computer.  If you're a developer, you can also use these links to download and redistribute the .NET Framework with your apps.

If you're using one of the latest versions of the Windows or Windows Server operating system, the .NET Framework might already be installed on your computer.  If you are a developer, you will typically install the .NET Framework as a part of Visual Studio.  Note that installing a new version of the .NET Framework doesn't always replace a previous version.  For more information about versions of the .NET Framework and how to determine which versions are installed on a computer see .NET Framework Versions and Dependencies or How to: Determine Which .NET Framework Versions Are Installed.  Use the following table for quick links, or read further for details.

 

.NET Framework version	Included in	You can also install on	Quick links
4.5.1	Windows 8.1 Windows Server 2012 R2 (to use Visual Studio 2012 or other IDEs, install the developer pack)	Windows 8 and earlier                   Windows Server 2012 and earlier                   (for a full list, see system requirements)	Download page for 4.5.1 web installer Download page for 4.5.1 offline installer
4.5	Windows 8 Windows Server 2012 Visual Studio 2012	Windows 7 and earlier                   Windows Server 2008 SP2 and earlier                   (for a full list, see system requirements)	Download page for 4.5 web installer

For a general introduction to the .NET Framework for both users and developers, see Getting Started.  For information about deploying the .NET Framework with your app, see the deployment guide.  To read about the architecture and key features of the .NET Framework, see the overview.

Installation choices

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The download links in this article provide the installers for the .NET Framework 4.5 and 4.5.1. These installers download the .NET Framework components for an app or control that targets those versions of the .NET Framework.  These components must be installed on each computer where the app or control runs.  Both installers are redistributable, so you can include them in the setup program for your app.

The download page is provided in several languages, but most of the downloads are provided in English only.  For additional language support, you must install a language pack.

Two types of installation are available:

• Web installer (web bootstrapper) downloads the required components and language pack that matches the operating system of the installation computer from the web.  This package is much smaller than the offline installer but requires a consistent Internet connection.  You can download the stand-alone language packs to install additional language support.

• Offline installer (stand-alone redistributable) contains all the required components for installing the .NET Framework but does not contain language packs.  This download is larger than the web installer.  The offline installer does not require an Internet connection.  After you run the offline installer, you can download the stand-alone language packs to install language support.  Use the offline installer if you cannot rely on having a consistent Internet connection.

Both web and offline installers are designed for x86-based and x64-based computers (see system requirements), but do not support Itanium-based computers.

To install or download the .NET Framework

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To install or download the .NET Framework from the Microsoft Download Center, follow these instructions.  You can also use the links in the table to download the .exe files directly.

1. Open the download page for the .NET Framework version you want to install:

   • .NET Framework 4.5.1 for all operating systems (web installer or offline installer)

   • .NET Framework 4.5

2. Select the language for the download page.  This option does not download the localized resources of the .NET Framework; it only affects the text displayed on the download page.

3. Choose Download.

4. If prompted, select the download that matches your system architecture, and then choose Next.

   You can also use the links in this table to download the .exe files directly:

    

   	Web installer	Offline installer
   .NET Framework 4.5.1	NDP451-KB2859818-Web.exe	NDP451-KB2858728-x86-x64-AllOS-ENU.exe
   .NET Framework 4.5	dotNetFx45_Full_setup.exe	dotNetFx45_Full_x86_x64.exe

5. When the download prompt appears:

   • If you want to install the .NET Framework on your computer, choose Run, and then follow the prompts on your screen.                      —or—

   • If you want to download the .NET Framework for redistribution, choose Save, and then follow the prompts on your screen.

6. If you want to download resources for additional languages, follow the instructions in the next section to install one or more language packs.

If you encounter any problems during the installation, see Troubleshooting Blocked .NET Framework Installations and Uninstallations.

Installation notes:

• The .NET Framework 4.5 redistributable was updated on October 9, 2012 to correct an issue related to an improper timestamp on a digital certificate, which caused the digital signature on files produced and signed by Microsoft to expire prematurely.  If you previously installed the .NET Framework 4.5 redistributable package dated August 16, 2012, we recommend that you update your copy with the latest redistributable from the Microsoft Download Center.  For more information about this issue, see Microsoft Security Advisory 2749655 and Knowledge Base article 2770445.

• The .NET Framework 4.5.1 is an in-place update to the .NET Framework 4.5.

• The .NET Framework 4.5 and .NET Framework 4.5.1 replace the .NET Framework 4.  When you install these versions on a system that has the .NET Framework 4 installed, the assemblies are replaced.

• Uninstalling the .NET Framework 4.5 also removes pre-existing .NET Framework 4 files.  If you want to go back to the .NET Framework 4, you must reinstall it and any updates to it. (See Installing the .NET Framework 4.)

• You must have administrative credentials to install the .NET Framework 4.5 and .NET Framework 4.5.1.

To install language packs

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Language packs are executable files that contain the localized resources (such as translated error messages and UI text) for supported languages.  If you don't install a language pack, .NET Framework error messages and other text are displayed in English.  Note that the web installer automatically installs the language pack that matches your operating system, but you can download additional language packs to your computer.  The offline installers don’t include any language packs.

                   Important                

The language packs don't contain the .NET Framework components that are required to run an app, so you must run the web or offline installer before you install a language pack.

1. Open the language pack download page for the .NET Framework version you've installed:

   • .NET Framework 4.5.1 language packs

   • .NET Framework 4.5 language packs

2. In the language list, choose the language you want to download, and wait a few seconds for the page to reload in that language.

3. Choose Download.

The following table lists the supported languages.

 

Language	Culture
Arabic	ar
Czech	cs
Danish	da
Dutch	nl
Finnish	fi
French	fr
German	de
Greek	el
Hebrew	he
Hungarian	hu
Italian	it
Japanese	ja
Korean	ko
Norwegian	no
Polish	pl
Portuguese (Brazil)	pt-BR
Portuguese (Portugal)	pt-PT
Russian	ru
Simplified Chinese	zh-CHS
Spanish	es
Swedish	sv
Traditional Chinese	zh-CHT
Turkish	tr
US English	en-US

Next steps

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• If you're new to the .NET Framework, see the overview for an introduction to key concepts and components.

• For new features and improvements in the .NET Framework 4.5 and the .NET Framework 4.5.1, see what's new.

• For detailed information about deploying the .NET Framework with your app, see .NET Framework Deployment Guide for Developers.

• For changes that affect the deployment of the .NET Framework with your app, see Reducing System Restarts During .NET Framework 4.5 Installations.

• For information about migrating your app from the .NET Framework 4 to the .NET Framework 4.5, see the migration guide.

• You can also download the source code for the .NET Framework 4.5 class library, to assist with debugging.  The source code is available from the Microsoft Shared Source Initiative website.  To access the source code and symbols from Visual Studio on demand, follow the instructions in How to: Debug .NET Framework Source.  See the .NET Framework 4.5 blog for additional information.