Rendering is only so that you can watch it smoothly on the timeline while editing. You don't need to render before outputting.
Premiere Elements 12 Mac. Have you updated 12 to 12.1 Update yet? If not, please do so using an opened project's Help Menu/Update.
Timeline Rendering is only possible if the render color indicator line is orange. That is the program telling you that you are not seeing the
best possible preview when viewing your Timeline content in the Edit area monitor. You do not have to render the Timeline in order to continue in
the workflow to its destination - file saved to computer hard drive or burn to product where the end result can be good or flawed.
Timeline Rendering advantage is that is your window of opportunity to catch a problem sooner than later - especially useful for titles, effects,
transitions, and non native formats. And, you cannot assume that an unrendered Timeline that looks "good" is going to give you a good end product.
So, consider the pros and cons of the Timeline Rendering. If you do decide Timeline Rendering is the better way for you to go, then keep a
watch for probable pile ups of preview files in the Adobe Premiere Elements Preview Files Folder.
More information on all this if needed.