The Unity Hub intermittently disables the entire File menu, as well as part of the Unity menu and also many keyboard shortcuts (like F for focus, etc). The error is intermittent, but once it appears nothing except a full reimport seems to fix it — but only temporarily. Cf. https://forum.unity.com/threads/menu-items-disabled-after-playing-in-editor.443568/#post-3425982 I've created a case for this bug. The number is 1014167.