If you are attempting to install the Unreal Engine 4.10 or later and you experience the following error message, please see the answer below for the solution and additional information.
Install Failed
VS2015 Prerequisites are required for UE4 and these failed to install due to missing Windows updates on your system. Please run Windows Update to resolve the issue.
In UE 4.10 and later, the binary download of the engine will require the Visual Studio 2015 redistributable components to be installed for the editor to run. The redistributable components are not the same as the full Visual Studio 2015 installation, but are just a handful of DLLs that any VS2015-compiled program needs.
Microsoft typically installs these automatically with Windows Update, but Epic includes Microsoft’s standalone installer with the engine for anyone that has Windows Update disabled or isn’t up to date. There is an issue however where on Windows 7 and 8, it requires previous Windows updates to be installed to run correctly, and will fail without them. The launcher will give an error as shown above, and although the engine is installed, it will give an error about missing DLLs if you try running it.
To resolve this issue, please run Windows Update to patch to the latest version of your operating system.