Can't find a solution to this problem though I have found threads where it was discussed. My wife's Galaxy S3 goes to mute from full volume automatically. She is not hitting the volume button to cause this. Sometimes it does it within minutes of her turning the volume back up. I read some threads that seemed to indicate an app was causing this but no one said which one. One person mentioned AVG but it was not clear what he was saying. Has anyone seen this behavior?