i have the exact same problem. this has happened to me thrice already within a span of 2 days - when i attempted to open an mp3 file, media master went blank. i was not able to find how to end the process either from task manager. i then had to shut the system down and restart. i wonder if this is a genuine issue with this application. because if so, we could consider removing it altogether from the system and finding a more robust software for listening to music.