The .NET Framework setup team has released an updated version of the .NET Framework Repair Tool that adds support for diagnosing and repairing issues with .NET Framework 4.5 and 4.5.1. This repair tool can identify and fix issues with the installation of MSI-based versions of the .NET Framework, but it cannot fix issues related to versions of the .NET Framework that are installed as a part of Windows.
If you run into installation issues with the MSI-based versions of the .NET Framework 2.0 SP2, 3.0 SP2, 3.5 SP1, 4, 4.5 or 4.5.1, I strongly encourage you to download the .NET Framework Repair Tool and run it to see if it resolves your issue before resorting to trying the .NET Framework cleanup tool. Here are links that you can use to find additional information about the .NET Framework Repair Tool:
- Knowledge base article - http://support.microsoft.com/kb/2698555
- .NET Framework Repair Tool download location - http://go.microsoft.com/fwlink/?LinkID=246062
- Blog post introducing the new version of the .NET Framework Repair Tool - http://blogs.msdn.com/b/dotnet/archive/2014/04/28/introducing-the-microsoft-net-framework-repair-tool.aspx