Not enough space for Music DB. Please free 200 mb

[gknoke]

I get the same message after having loaded songs from iTunes on my Mac.  How do I reduce the 200mb?  Also, sometimes my Mac detects the player as a device, and sometimes it doesn’t.  And why doesn’t it say “7.8 GB” rather than “8GB” so fewer of us have this problem?  And how come the “manual” is so grossly insufficient to deal with any issue?  Obviously one gets what one pays for.