Hi,
For a while I've had a problem when copying some music folders to the N95 using a card reader or Data Transfer mode in that once copied the phone will not show them. They don't appear in File Manager and the Music Player also can not see them.
After months I think I've tracked it down to the "System" folder attribute. In Windows explorer you can add a column called Attributes. When I added this I noticed that the troublesome folders had an "S" attribute.
This can not be turned off by right clicking the folder in the same way as "read only" can be for example.
There is a dos way of removing this System attribute but I've found it easier just to create a new folder.
I don't know how many people this effects but you may have copied large numbers of albums to your phone but not noticed that some do not play in Music Player - this is what happened to me as I tend to play music on random.
Oddly, I recently went though a process of moving all my music to new folders as I suspected it was a folder problem and some of the new folders I created now have this "s" attribute so I'm not entirely sure how it gets there. :con?