I was trying to install Microsoft DirectX SDK (June 2010), which was downloaded from here. The installation failed with the following error dialog:
Setup failed. Errors were encountered during installation of redistributable packages. Please close all open programs and try running setup again. If problems persist, contact DirectX Developer Support. Error code: S1023
Needless to mention that even when it was run after closing all open programs, it failed again with the same mysterious error code.
The problem seems to be caused because my Windows has a Visual C++ 2010 Redistributable that is newer than the one that this SDK is trying to install. The solution, explained here, is to uninstall all the Visual C++ 2010 Redistributable packages and try installing this SDK.
I found that I had the following two packages:
Microsoft Visual C++ 2010 x64 Redistributable - 10.0.40219 Microsoft Visual C++ 2010 x86 Redistributable - 10.0.40219
I uninstalled them and the DirectX SDK installed without a problem after that.
Tried with: Windows 7 x64