I've just upgraded to PE8. On opening a project originally created in PE7, I pressed ENTER to have PE8 render a preview. The rendering progress box briefly appears and playback starts, but in very bad quality and the line on top of the timeline is still red (it should be green after rendering the preview).
Any suggestions? I searched some forums but did not encounter similar issues; I did have the uncheck "Enable GPU playback" to get preview working.
We always recommend against opening a previous version project with a newer version of the program. There are almost always funky problems like this.
Double-check to make sure the Work Area Bar covers your entire project.
If that doesn't fix it, I'd very much recommend you finish your version 7 project in version 7 and begin your next project in version 8. Otherwise this -- and other problems you have not seen yet -- are pretty likely. sorry.
You can also export your close-to-finished video from version 7 (using Share/Personal Computer/AVI) and import that into your version 8 project for finishing.
This sounds like the WAB (Work Area Bar) might be set to a smaller portion of the Timeline, and Rendering is restricted to that. I will hit the \ (Backslash key) to zoom to the max Duration of the Timeline, and then Dbl-click the little box in the middle of the WAB to expand that to the full Timeline. This shows the WAB:
Hope that helps, and good luck,