On the Fuze, the DB refresh will occur during if one of the two conditions is met.
1. The SD card is removed from the player for whatever reason.
2. ANY write activity on either the Internal Memory or the Micro SD card.
Now you say you did not do any file transfers, but sometimes you might be doing write activity without you knowing about it. For example, if I even START Winamp while my player is detected, the Winamp files get rewritten by Winamp, and forces a DB refresh. If I start Rhapsody while the Fuze is connected, Rhapsody updates some of it’s database files located on the device, (such as updating the license information) and again will force a refresh.
So what may be happening is some external application may be causing write activity even if you don’t know it. For example, your computer may have a setting where it indexes your removable drives and saves that index information on the Fuze. Thus you get a refresh. Or, media player 11 may be accessing the device and placing alternate album art thumbnails on the device…same thing.
So next time it happens, you need to see if perhaps you have a background running App that is secretly writing to the Fuze.
If the ONLY thing you are doing is charging, and no apps are accessing the drive, you should NOT get a refresh.
Another helpful hint is if you are using MSC mode, you can use the safely remove hardware wizard to “disconnect” the data link from Windows. This will ensure no apps are accessing the drive, but the power connection will still be active and you can still charge.
Just a couple things to think about.