# objects do not render [duplicate]

I must be making some silly mistake but I can't see it... I have a document with some objects on a layer (metaballs) and 1 cam. The layer is enabled, the objects have preview and render ticked. The objects have Max draw textured. The renderer is cycles. The objects have nodes shaders.

Two 3dviews are open. both are aligned to cam. The cam has been pointed at the objects. Both are in object view. One shows the objects in all draw modes. The other shows the objects in no draw modes. The objects do not render. I have restarted blender.

What am i doing wrong? (2.79b)

Another thing I notice is the working mballs seem to have an orange icon with their name that expands to a white icon with the same name. eg mball.005 contains mball.005. the broken mballs seem to be mixed up - the names don't match. e.g. mball.010 contains mball.012. Renaming the child elements doesn't seem to fix things but maybe it indicates something got corrupted. Pure speculation...

Regards

update: I pushed it out to an obj, factory reset blender and brought it back in. apart from needing the nodes rebuilt all is back to normal. it's made all the metaballs into single objects which I couldn't work out how to do, so in fact it's actually done me a favour.

I'd still like to know what I did wrong to mess up the file...