music in presentations

Music in a presentation is not consistent. Songs work for 1 or 2 presentations then quit. I use several songs repeatedly in a slide show at church. They work at home, but seldom do when used at church. Have to re-insert them before running the show. Most of the time but have to be re-named when they quit. Need a way to delete the multitude of non-working music so they can be started over. Better yet make the program stable enough to not need this function.
Using Linux 18.8. and Libre office Version: