Hi!
This is a software problem. The software on my Android phone reads the music files on SD card once. When I restart the phone it starts playing immediately. The software from Pioneer tries to read USB/SD every time you turn on the unit or even when you switch from one AV to another. Sometimes it hangs for about 2 minutes when I switch from video to music on same AV.
I contacted Pioneer's support but they ignore the problem.I'm thinking in return my unit to store. It's useless. Today it takes more than 5 minutes to resume the song it was playing yesterdar when I turned it off.