Fabio,

VFP will cache the class definition in memory forever, it will not garbage collect it. The only time this is ever a problem is during development and you get an "in use" error when trying to MODIFY CLASS.

Unless the class is huge and you are having memory issues just leave the class in memory.

>for release class loaded on memory, but without instance,
>VFP clear they automatically or is need to execute a periodical
>CLEAR CLASS or CLEAR CLASSLIB.