Occurs on Windows Server 2008 SP2 or very old Windows 7 builds. Fix: Download and install wic_x86_enu.exe (or x64) from Microsoft before retrying the .NET installer.

For system administrators deploying via WSUS or SCCM:

Improved startup times and reduced memory usage for desktop applications.

The file is the official offline installer for Microsoft .NET Framework 4.5 .