I purchased Garageband II, and everytime I download it, it closes and then when I go to reopen it, it just downloads again and I cannot open the actual program. What is wrong?
After GarageBand has completed downloading and installing all of it's extras, remove the GarageBand preferences file and relaunch GarageBand. This took care of it for me.
To do this in the Finder:
This should take care of this problem.