I am trialing a CC version of Lighhtroom and when I try and preview a slideshow Lightroom crashes. Windows 8.1 operating system with GPU acceleration off. This seems to be a well reported issue but with no solution. If it is not fixed I will not purchase CC.
You don't need to preview at high quality. Try reducing to standard or even draft. The slideshow will render as high quality when you export to video.
If you are still getting problems with preview try exporting as MP4. Does it then play OK in Windows Media Player?
Preview in any mode causes a crash, even Playing causes a crash as well. I tried exporting as MP4 and that also caused a crash. Thanks for the suggestion though.