Problems with a fresh install and Rekordbox freezing

Hi

Ive recently purchased a new desktop. Reinstalled Rekordbox-couldnt remember my previous log on so just did a complete fresh install. I have no idea whether this is anything to do with whats happening-but anyway. I can open it up. Drag and drop files. Use the complete functionality of the software but as soon as I put in a USB I get 'Importing Histories' and a progress bar that never moves. 

If I then shut down that box the entire thing crashes. Its freezes-and I have to force it to shut down via Task Manager.

This is driving me nuts. Can anyone help?