All of my apps that had audio/visual content (YouTube, Show Box, even the internal video player in LP operating system) had been out of sync and I performed the tip from the link below. I have literally just tried it and it seems to be working from doing it. I took my Micro SD card out just in case it deleted anything but all of my files are still on my phone's internal memory and the problem has been fixed. It's a very simple process and takes virtually no time at all.
h t t p :// w w w . solvemix . com /index.php/android-smartphones/322-samsung-galaxy-s5-problems-after-android-lollipop-5-0-update-tips
PS: You'll need to cut the spaces from the URL as it wouldn't let me post a link (my first post and I need 10 apparently)