If you do not have a Unity license activated, Projects will not open. Once you have assigned the license seat to yourself or another user in your Organization (for Plus, Pro & Enterprise only), there are a couple of ways to activate, depending on your network situation. I have already activated a license on my machine, but the Unity Hub is saying I have no valid license.I have used Unity Personal, but would like to update the Editor to my new Plus, Pro or Enterprise license.I would like to activate a Personal, Plus, Pro or Enterprise license.