What computer operating system is your Premiere Elements 13 running on?
There is a render indicator line over the Timeline content. This line is orange, not red, when the program wants to tell you that
it is not giving you the best possible preview of the Timeline content when it is playback in the Edit area monitor. If you see no colored line or a green one,
that is the program telling you that it is giving you the best possible preview. No Timeline rendering is possible under that condition because you are getting the best possible preview according to the indicator line.
A just in case screenshot to make sure that we are OK on where to look for this line
The above screenshot represents the situation in 11, 12, and 13 and is actually from 12. I present this since
your description mentions a red indicator line (from the days of version 10 and earlier) and not an orange line
for version 11, 12, and 13.
In order to render Timeline content, the gray tabs of the Work Area Bar need to span the Timeline content
to be rendered.
What are the properties of these source media that you cannot Timeline render? Timeline rendering is for
preview purposes and will not fix an issue in the Timeline content. It is a window of opportunity to catch a
problem sooner than later.
Please excuse if I have written what you already know. I did not want to take anything for granted. If none of the
above considerations apply to your situation, then....
If you are experiencing a Premiere Elements 13 settings file problem, you can rule that out or in by deleting
the Adobe Premiere Elements Prefs file or the whole 13.0 Folder in which it exists.
Local Disk C
and in the 13.0 Folder is the Adobe Premiere Elements Prefs file. Be sure to be working with Folder Option
Show Hidden Files, Folders, and Drives active so that you can see the complete path cited.
Also, we can go into video card/graphics card information, latest version of QuickTime installed, running program from
User Account with Administrative Privileges, antivirus or firewall involvement, pen and tablet interferences, free space where
you have the preview files directed, etc.
Please review and consider and then we can decide what next.