Quote Original restart became to lengthy. Hopefully prior misunderstandings have been resolved. Such as:
1. Did not start the project with the edit system's Produce phase.
2. Not starting with Produce caused edit system to use pds as the starting file format.
3. Did not realize pds format creates many nested inserts.
4. Nested inserts caused edit system to block audio editing which is needed.
5. Mouse double-clicks on Timeline segment to open audio editing failed. Caused system to only "update Thumbnails". ??

Found informative CyberLink article titled "How to convert Cyberlink PD pds video to mp4. (Also applies to avi or other formats).
Seems useful since my source files are all avi format.
My restart will begin with the four conversion to avi steps in the article.

Please respond if you have knowledge this article is outdated or has erroneous info.

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10/13/21 7:30 PM Started with first two instructions in Step 1 of the CyberLink article.
1. "Run PD".
2. "Click on File > Open Project in upper left corner".

Opened edit pgm. Clicked on File > Open Project.
RESULT: Notice appeared at center of work area. "You have not saved changes you made to current project. Do you want to save the changes now?".

Question 1 - My input file going into this is the edited output file from my prior editing session. It was saved then. Why does editing pgm say "you have not saved changes........"?

Question 2 - .........do you want to save the changes now"? I clicked on "No". Edit pgm responded with display of Windows 10 File Explorer page showing the edited work file from the prior editing session. Should I have responded "Yes" which would be the second save for the same thing?

After all the mis-cues in Restart # 1, just trying to be ultra-careful and wait until an answer from someone.