I am completely unable to set my viewing pane in Mail on High Sierra so that the message list appears on the left, with lines from the message, and the message appears on the right. See Use Mail on your Mac - Apple Support,which pictures the view that I am seeking. All my email view Preference produce a full screen of message lists and require double clicking to open.
MacBook Pro, macOS High Sierra (10.13.2)
If you are using Mail in full screen mode, temporarily change it to windowed mode instead. You can do that by selecting Exit Full Screen from Mail's View menu. Or, quit Mail, and hold a shift key while launching Mail again from Applications or the Dock.
Position your cursor on the rightmost edge of the Mail viewer window. When positioning your cursor over it, the normal selection cursor will change and bear a resemblance to this
<-|
Drag that.
Drag that cursor to the left. Drag it farther than you have been doing, much farther. There will be no visual confirmation of that action until you drag it more than halfway to the opposite edge of the window, or full screen if you are not using windowed mode.
If you are using "Classic View":
The horizontal slider described above becomes a vertical one. In that case you will be dragging the bottom part of the Mail window up.
If you are using Mail in full screen mode, temporarily change it to windowed mode instead. You can do that by selecting Exit Full Screen from Mail's View menu. Or, quit Mail, and hold a shift key while launching Mail again from Applications or the Dock.
Position your cursor on the rightmost edge of the Mail viewer window. When positioning your cursor over it, the normal selection cursor will change and bear a resemblance to this
<-|
Drag that.
Drag that cursor to the left. Drag it farther than you have been doing, much farther. There will be no visual confirmation of that action until you drag it more than halfway to the opposite edge of the window, or full screen if you are not using windowed mode.
If you are using "Classic View":
The horizontal slider described above becomes a vertical one. In that case you will be dragging the bottom part of the Mail window up.
John Galt ~ Many, many thanks! It took many tries before the inner text (and not the entire window) moved, but I got it, which I could not have done by myself!
OS 10.13.2 How to set viewing pane in Mail
