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The Microsoft .NET Framework 4.5.1 Release Candidate (RC) Developer Pack is available for Windows Server 2012, Windows Server 2008 R2 Service Pack 1 (SP1), Windows Server 2008 Service Pack 2 (SP2), Windows 8, Windows 7 Service Pack 1 (SP1), and Windows Vista Service Pack 2 (SP2).

The .NET Framework 4.5.1 RC Developer Pack installs the multi-targeting pack for the .NET Framework 4.5.1 RC. Developers can build applications that target the .NET Framework 4.5.1 RC by using either Microsoft Visual Studio 2012 or third-party IDEs.  

This package installs the following components:

  • The .NET Framework 4.5.1 RC

  • The .NET Framework 4.5.1 RC Multi-Targeting Pack: Contains the reference assemblies that are required to build apps that target the .NET Framework 4.5.1

  • The .NET Framework 4.5.1 RC Language Packs

  • The .NET Framework 4.5.1 RC Multi-Targeting Pack Language Packs: Contain the IntelliSense files that help to build apps that target the .NET Framework 4.5.1 RC through Visual Studio 2012 and third-party IDEs.

Note If you intend to redistribute the .NET Framework 4.5.1 RC, you should use the Web Installer package instead of this package. To obtain the Web Installer package, go to the following Microsoft Download Center website:

Microsoft .NET Framework 4.5.1 RC (Web Installer)

More Information

Download information

The following file is available for download from the Microsoft Download Center:
DownloadDownload the package now.

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to obtain Microsoft support files from online services Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

What’s new in the .NET Framework 4.5.1 RC?

The .NET Framework 4.5.1 RC supports the writing of code in C#, Visual Basic, and F# programming languages, and includes these significant language and framework enhancements:

  • Better performance and reliability

  • ASP.NET application suspend and resume

  • On-demand compaction of the large object heap

  • 64-bit Edit and Continue

  • Activity tracing and sampling

  • SQL connection resiliency

  • Managed return values

For more information about these and other features of the .NET Framework 4.5.1, see the .NET Framework Developer Center website and blog post. This version of the .NET Framework runs side-by-side with the Microsoft .NET Framework 3.5 Service Pack 1 (SP1) and earlier versions, but performs an in-place update for the .NET Framework 4 and the .NET Framework 4.5.

Command-line switches for this update

For more information about the various command-line switches that are supported by this update, see the "Command-Line options" section of the following MSDN website:

.NET Framework Deployment Guide for Developers

Supported languages for this update

For more information about the languages supported by this update, see the "Supported Languages for Developer Pack" section of the following MSDN website:

.NET Framework Deployment Guide for Developers

Restart requirement

You may have to restart the computer after you install this software if any affected files are being used. We recommend that you close all applications that are using the .NET Framework before you apply this update.

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