The best option here I think would be to follow essentially the steps you would with a new RC, but using the official release:
- Download the trial version of 3.0.
- Without uninstalling your current beta, install the trial, choosing the same location for the installation as your beta (note that the default for the beta was to install to a directory named “Scrivener”, whereas in the release it is “Scrivener3”–so you will probably need to change this to match the location you currently have)
- Run the trial and create a new project or open an existing one, then go to File > Options and save your preferences to file via the Manage… button.
- Close Scrivener and uninstall it. If any part of the “Scrivener” or “Scrivener3” installation directory remains (as it might do, from having installed over the beta version), delete it.
- Reinstall the trial version to whatever location you want.
- Return to Options to load your saved preferences.
Uninstalling clears the program settings, which currently are stored in the registry, so this will let you save them but then ensure that you’re working with a clean installation once you get going.