Fails to create library in latest version of rekordbox

Hi,

I've been adding tracks into rekordbox for the last month whenever time was available and the process worked fine.

Today I added some more albums and synced the playlists , then clicked the create library/eject icon.

This went up to about 18% then came up with the failed to create library message and then the disconnect drive.

I've tried this now a few times with the original hard drive and with another one with no joy.

The drive is an Buffalo 500gb external hard drive and the other one is a WD Elements 1tb external hard drive, my computer is running windows 7 and I'm creating the playlists for the XDJ-R1.

Please can someone help .

Thanks.

Lee