Seems the new RomCenter 3.6.0 version have issues with hash info of the roms when it is in upper or lower case, then RomCenter thinks that the rom not exist or is unknown, and delete the rom accidentally (when you try repair all roms and impossible to recover)
Removed files are moved to an archive folder by default (see settings/general). If you disabled the option, they are moved to the dustbin. In both case, you can restore them.
RomCenter wrote:Are you using a plugin ? (help/about/plugin)
is clean install, and in (help/about/plugin) only show: arcade.dll version 1.8
RomCenter wrote:Removed files are moved to an archive folder by default (see settings/general). If you disabled the option, they are moved to the dustbin. In both case, you can restore them.
then there is other bug, because in setting is set to default "recicle bin", but in recicle bin there is nothing xD