sansa clip zip rpoblem with skipping files randomly


I have new device wich is sansa clip zip. I have problem while playing music from files.

It is skipping files randomly. Sometimes playing few seconds of other sound and coming back to play proper one.

It is happening when playing different formats like mp3 and flac.

What schould I do ?

I did a little research … now i am sure that problems with file playing are always connected with file quality.