music library slow

Ive added my music which is on an external hdd to the library

but when i click on an album i get the message with the loading bar saying loading media information from files

and that takes about 20 secs for each album but when its dont that once i click and go straight into the album with no loading

i will be using this set up as a juke box for people to use so it needs to be smooth and this is a bit of a project killer at the moment

is there anything i can try to solve this?

thanks