I finally found that my BitDefender total security don't allow Poser 12 to write the render cache So after i have add an exception to permit this in my antivirus settings ,Poser 12 render is now displayed and i can save it

Still not possible to see the render pictures after rendering in Poser 12 trial (just grey screen a second after render displayed ) and poser 12 trial crash very too often on my Windows 10 pro 64 bits , 32 gig Ram. I think i will wait before i buy it and continue to Poser 11

Try to uncheck "separate process" . This should do the trick. At last for me it does.