LaurieA: Glad someone else has the problem. I was starting to think it was only me, The problem is the flashing colour as the mouse moves drives me nuts.

Razor42: Sorry about the low res. I was unsure as to how big an image the post would accept.

The blob is several stone props ( bought from Daz 3D ) stacked to make a pile of rocks so that the green represents several different surfaces, although they all have the same material. It does not happen on all objects. I have noticed it on props I have made myself where it appears to be material related. It does not occur on the Genesis figures. The image above has the viewport set to texture shading. If I change it to Iray, the colour is initially there but vanishes once the viewport starts to render. The full render in Iray is OK. There are no errors in the log. Some warnings relating roaming directories and lots of Not initialised in the GL section.