Im not sure that ProSeries actually saves a copy of any pdf attached for EFiling within the program itself. 

You chose the file from your hard drive, it's attached and sent along with the Efiled returns.  If you've deleted that file from your hard drive, you may not have access to it any longer on your end.

If this isn't what youre referring to, you may want to rephrase your question.

Will keep you posted. Intuit needs to answer my question.

@IntuitGabi  Can you confirm whether the attached pdf files are saved within the program at all, or only on your hard drive?

Its my understanding that ProSeries will NOT save any attached PDF files for you.  That would be your responsibility, same as saving a PDF copy of the return.    There doesnt seem to be any confirmation one way or the other anywhere though.

You're right @Just-Lisa-Now- . Confirmed that attached PDFs are not saved in the return, they're saved on the computer.