Using Classic Outlook on Windows for personal email, calendar, and contact management
I too had Googled this feature, and came across this thread. I was just about to revert from "New" Outlook, and included this in the reason for reverting, which prompted a help article: https://support.microsoft.com/en-us/office/display-the-total-number-of-messages-in-a-folder-in-outlook-1f47664e-2468-4f0e-8515-4e0596f9553a#PickTab=New_Outlook&picktab=new_outlook Looks like hovering provides this info - I think this helps others issues.