Well, reinstalling the application makes sure that you are running the latest executable, so my bet would be that the installation directory is not writable by the software without admin rights. The safest solution would be to uninstall the software completely (then make sure that no files left in the installation directory), then installing it again (same place is fine), and let the software download everything itself. The main issue is that there are less files in the installer now, and these old files are not deleted when you reinstall the app. Because they are protected files from the previous installation they can not be updated by the app itself at the moment. If they were downloaded by the program then it will be able to update them later on.