Thanks for the posting on Adobe forums,
Please check for the scratch disks locations;
Please try to make it local on the disk.
You may also want to ensure you have the latest version of Quicktime from Apple.
Your question is a long standing issue that seemed to have peaked around Premiere Elements 8.0/8.0.1 and seems to be independent of computer operating system, scratch disk locations, and QuickTime versions among other things. And Adobe has not come out with an explanation to date as far as I have ever seen.
But, let me make sure that I am interpreting your question correctly.
Are you saying that, after you save/close a project whose Timeline had been rendered for preview purposes, the re-opened project presents with an orange line over the Timeline content with the implication that you are looking at an unrendered Timeline? If that is the case, please read on.
I will dig out the unabridged version of what I have written about this in the past. But, for now, the abridged version.
1. Although the color indicator implies that the Timeline content is "unrendered", that is, you are not getting the best possible preview of what you are seeing in the Edit Mode monitor preview, the preview files that were originally generated are alive and well in their hard drive save location. Best guess is that the link between the preview files and the project are getting broken and are not repairable, short of rendering the Timeline content again if absolutely necessary for preview purposes.
2. In the re-opened project, rendering again to turn the orange line to green (best possible preview) can be done for the whole of the afflicted content or selectively (just segment) by setting the WorkArea Bar gray tabs to span just the area to be rendered.
3. My philosophy on this is to move on or re-render all or part if indicated. You have rendered the area previously and should know what that is going to look like...unless of course you make changes in the re-opened project.
This one has an unforgetable history going back several versions and apparently surfacing again in the present and still without the whys.
Please review and let us know if I have targeted you question.
You have interpreted my question fully and really answered my concerns. I can live with the issue and will render as required. Everything else is functioning well.
Thanks for your support. I am an 84 year old great grandfather, editing a number of old videos and movies for my family.I have premiere pro but I am hoping that using Premiere Elements will make the task a little easier and faster.
Thanks for the follow up.
You are working on a great project that will be cherished by your family. Best wishes. It is such a wonderful gift to your family.
Please do not hesitate to ask if you need clarification on anything written.