F12 Render button only shows OpenGL render!

I have a very simple but annoying problem.

I have Cycles as default render engine. I can use render mode in viewport. But… when I want to do a render with the “render button / F12” I get an OpenGL render! All the times.

I have no way to do a Cycles render. Every time I press any render button possible, I get a OpenGL render.

Someone knows the reason, or can help me? :S

PD: Blender 2.74

Please supply a blend file that shows the problem.
Can you also show screenshot of your 3d view and the render

Thanks for your response Richard. I got it fixed by creating a new file and import on it, all objects from original .blend file.

I think it was a bug :wink: