I notice this in an other project and test it with 2.78c and the last build. I made a simple scene to report it. Just hit F12 and you see the particles are not rendered. If you check the "eye" for viewing particles in viewport, it works in the render.
I cannot confirm that here, I do get particles when hitting F12 even when they are hidden in the viewport… Can you please try the latest build from our buildbot (if not yet done, not clear to me from your comment).
Also, please always give us your exact Blender, OS and GPU (including drivers) versions, as requested in the template!
I've tested with the lastest build and it's the same thing.
I use Blender 2.78c x64, Windows 10 x64 and a GTX 780 6Gb to render (drivers 382.05). I tried to render with the CPU and it doesn't work too.
Wellll… don’t know what to say here, only have CPU rendering, but with both 2.78c and current master it works as expected for me. :|
We need some more testers here!
Also, what happens for you if you try using Blender Internal renderer instead?
I tested with Blender Render and same thing. So, I desactivated all add-ons installed excepted Cycles and it works so it seems it comes from an add-on, I have to find which one.
EDIT : I found, it's an add-on named Timecode which allows to display the timecode in the 3D view : https://github.com/RayMairlot/Timecode