I've searched and searched for an answer, and even the local store didn't know how to fix this... So I updated the phone (Samsung Epic) a few months ago, and I had all of my notifications and ringtones set as custom, mp3 tones created on Ringdroid. After a while, I noticed that when the sound was on (not on vibrate) the tones wouldn't ring, and my phone would just silently light up like it was ringing but on mute. So I checked, and it wasn't on mute or vibrate, and my backup alarm, which is one of the default phone tones rang just fine. I checked the mp3s in my music player and it gave me the error message "player does not support this audio type" I was fine with not having mp3s on my phone, but then it told me that I can't listen to voicemail messages using the voicemail application, which is an issue. I restarted the phone, and all was well, then three days later, same issue. So I hard reset the phone (backing up all files), and then all was well, and then a few days later, same issue. Then I took it to the store, where they hard reset the phone again, and it worked for a few more days, and then again, same issue. Finally I realized that when it happened, if I unmounted and then remounted the SD card, it worked for a while, and then stopped again. Question: what the heck is happening, and how can I fix it? Thank you!