Somewhere between SqueezeCenter 7.0 Build 13599 and 7.0 Build 15528 (Windows Server 2003 - EN - cp1252), the ability to browse the Music Folder appears to have been broken. I just did a scratch installation of Build 15528, and re-scanned my music. (SqueezeCenter shows 460 albums with 6680 songs by 441 artists, as it should, but nothing appears in the left pane when browsing the Music Folder.)

Further investigation revealed that this problem is caused when I enter a UNC path for my music folder.  (For example, in my case it is \\Guardian-20\Flac).  If I map a drive to that same folder, it works properly.

This behavior can even be seen when setting up SC initially. If you enter a UNC path into the Music Folder field, and hit the Browse button, you will see the folder, but you can't browse it. (A mapped drive to the same location is also there AND it is browsable.)

Here is a forum thread related to this topic:  http://forums.slimdevices.com/showthread.php?t=41372