The useless message that I was referring to is the "An error occured preventing installation" message. (Typical programmer's message---might as well just have the install process crash and be done with it!) The message that you're referring to---i.e., the one advising the user not to uninstall prior to updating---appeared when I clicked on the "check for updates" menu item and the update checker found the 8.2.4 update.
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