Preferences that I set in the app do not seem to stick
If the welcome screen seems to appear every time you launch the app, or any preference you save in the app does not seem to stick, chances are the stored preferences are corrupt. One way to fix this would be to delete the preferences manually and restart the mac. To proceed, open Terminal.app on your mac and issue the following commands:
Quit 2Do. Restart the mac and relaunching the app again to recreate these preferences again.