can Not open Window > Navigation 2018.2

The title says it all, I click on Window to open Navigation and nothing is there. I’ve tried opening Navigation tab in other projects, but it doesn’t seem to work there either. Unity version 2018.2 Any solutions?

Well, first of all, if you can’t find the Navigation tab, it is under Window → AI → Navigation.
If you open it but the window still doesn’t appear, set Layout to Default in the top right corner of the Editor and try again.