Can't get Blender to render smoke I am having somewhat of a problem. I get a real nice flame and smoke in the Viewport but when I render only the fire does. I've been to other forums and tried different things but can't figure out what it is.  

This is a screenshot of the viewport

And this is a screenshot of the render 


Here's the link to the blender file if it helps. 

Thanks everyone.
Select the Flow object and make sure that the Flow Type: is set to Fire + Smoke. It is likely just set to Fire. If this doesn't help, consider uploading a .blend so someone can locate the problem more easily.

Edit:

Got it! The issue was in your nodes. I'm not quite sure what the issue was, but I replaced the current smoke nodes with this, which I plugged into the mix node that the other thing was previously plugged into:



The value in the multiply node affects how dense the smoke is. Here is the fixed .blend file: