If your Mac 5.0.5 will not launch or is freezing when entering full screen mode, follow these steps:
1. Close Evernote 5.0.5 entirely (also close the toolbar Helper)
2. Install Evernote 5.0.4 from here: http://cdn1.evernote...note_400704.dmg
3. Run Evernote 5.0.4
4. Exit full screen (this is important)
5. Update Evernote again from the menu: Evernote -> Check for Updates...
6. Feel free to enter full screen mode again after the upate
Reason: We hit an OSX bug where an alert dialog can stop an app going into full screen.