If you click on the "A" column, do you have any tracks/files with a red
If you have, do a right click and remove them from your Collection
Also to help with the freezing could you try this -
Go to Preference> General> Audio Cache (% Ram) - set to 0% (0MB)
See if this helps, I've always had to use this setting as I suffer from a slight freeze in the GUI if I don't. But it doesn't worry me
