If you are looking for the Upload button, you can find an Import link on the activities page that has mostly the same functionality. You shouldn't really need to use this link if everything is working correctly. If you've installed and configured Garmin Express correctly, it should upload your activities for you automatically (or with a single button click).
I load up my workouts daily. Since July 11th i keep losing the uploaded workouts. Yesterdays has gone now. very frustrating. makes my polar hem feel better as i can track what i am or not achieving.