I have two files, Robert&Liz, Shelia&Robert , File 1 went to CRA ,File 2 family overwrote File1 Robert PDF. Why do you not save as prior years full names

I did family one first , two tax files, saved as PDF , Liz and Roberts

I then did family two second , two tax files (now four) but when I went to save PDF's , Sheila was file but her Robert 's PDF file overwrote family one's Robert

Years ago you saved as RobertH or such. If I had note spotted the override msg by windows I would have not known. Thankfully I had a backup