Please make sure you have the latest version FileManager 4.0.
First make sure that you can upload / download files. A lot of times, anti-virus software or network security software might block it from accessing the Internet.
If you cannot see a file or folder, please try to refresh the folder. You can also try to logon www.drivehq.com, go to Storage & Sharing section. If you can see files there, then FileManager might have a problem. You can try either reboot your PC, or quit and restart FileManager.