Even with Classic Ribbon, the only preview options I have in the recent verion of Outlook are a dumbed-down Show or Hide. Gone is the option to see 3 lines of the content of each email. ChatGPT tells me that the options are still there in Office16 Outlook.exe and it recommends hat I start Outlook this way in the Office16 folder and then pin the running process to the taskbar and invoke from there:



Outlook /select outlook:inbox

But when I attempt this it launches a new install process that takes so long I think it is actually just hanging.

What can I do to restore this functionality?

It sounds like you got switched to New Outlook and want to go back to Classic Outlook.

Identify and Revert

Identifying and Switching Between New and Classic Outlook Interfaces

That's what I needed. Thank you for taking time to provide the link.