I have been running running Vegas Pro 13 for a long while and it works great. (64 bit on Windows 7/64). I upgraded to Pro 15, and with it, the preview screen in continually out of sync----you only see diagonal bars with good camcorder video---and with a jpeg still, it goes intmt. to black. The same video and jpegs display fine in Pro 13. I though maybe it was a GPU hardware acceleration problem, so I unselected that option, but it did not fix the problem.