GO TO "MYACCOUNT''; THERE'S A LINK THERE TO DOWNLOAD *ALL* OF YOUR PREP FILES FOR ALL YEARS.

THEN WHEN INSTALLING THE 2019 (?) PROGRAM, IT WILL ASK ABOUT THE PREP FILE & WHERE IT IS LOCATED.  POINT TO WHERE YOU DOWNLOADED THE PREP FILE.

BUT IT USUALLY ASKS IF YOU JUST WANT LACERTE TO GO ON-LINE TO GET THE PREP FILE.

*****

MAYBE EXPLAIN A BIT MORE WHAT HAPPENS/GOES WRONG WHEN YOU ARE TRYING TO INSTALL THE PROGRAM.