Songs randomly becoming unplayable on Samsung Galaxy S5. Why?

Sometimes when looking for a song to play on my phone, I see one that is unplayable. These songs all appear as the file name instead of their actual name (sometimes the file name is different so I can more easily search for it on my laptop) and under artist, it says, "<unknown>" and it has the wrong cover art. When I click un it, it says, "Sorry, the player does not support this type of audio file." How do I fix this? I'm tired of randomly having to redownload songs. Also, right before this issue, I updated the phone, I renamed the music folder of my SD card and created a folder. I use Star Music Tag Editor, if that makes a difference. Samsung Galaxy S5.