I am currently running Wing FTP Server 4.1.1 on a Windows 2008 R2 server. It seems that whenever a folder contains more than about 12,500 files (not sure of the exact number, but it is about that) you can't view the folder. I've tried viewing it in multiple internet browsers and FTP Rush and FileZilla FTP clients. I got the same results when trying all these methods. It will just show an empty folder.