My guess
river problem ... DirectX SDK ... Directx9 is the standard for all Unreal games ... Modern DirectX might miss the old goldies.
Others guessed it was the VC++: I found the solution! Go here
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and download the installer. Uninstall and dont repair. Then reinstall.
The Microsoft DirectX 2010 Redistributable package, which can be found here:
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Be sure to install it before trying to install the UE4 launcher, even if it is already installed there is a chance the package was installed by a game using a slightly older version. Try this if you are having difficulties.
Others said it was like: It was due to the msvcr120.dll in system 32. If you have the same problem. delete that first and try again. thats what I did.
Some even: Some users have had luck uninstalling and then reinstalling some of the well-known dependencies(directx, VCRedist, etc)