The Installer tells me that I do not have SSE 4.1! What is that?
It means that you have an older model of CPU that does not support all instructions Corona uses. Up to Corona Renderer 1.7 hotfix 2, you can still use a legacy build, which the installer will install automatically. It offers the same features and is fully compatible with the regular build but is a bit slower.
From Corona Renderer 2 onward, the legacy version will no longer be offered, and you will need a CPU that supports the SSE4.1 instruction set (that is, any processor from within the last 10 years). Here is a list of compatible CPUs.
From Corona Renderer 3 onward, the Licensing Server will no longer support CPUs without the SSE4.1 instruction set and is now a 64-bit only application (It will not run on 32-bit versions of Windows).