Mail App search not working
Since upgrading to Big Sur (which I dislike generally, by the way) the search feature in Mail App does not work properly: 0 results for all searches.
I can get it working by quitting Mail, restarting Mail while holding down the shift key (twice), then restarting the iMac. Search works beautifully. But then after a while it stops working again.
This problem occurred when I upgraded to Big Sur from Catalina. In an attempt to fix the issue I did a clean install of Big Sur. Same issue.
I have attempted to 'rebuild' the mailboxes by clicking on 'Rebuild' under the Mailbox menu. This hasn't help (obviously). It's not even clear that anything happens when I click on 'Rebuild': there is no indication that anything is happening or acknowledgement that I have clicked on the menu item.
iMac (Retina 5K, 27-inch, 2017), 4.2 GHz Quad-Core Intel Core i7
Big Sur 11.2.2
I would be very grateful if anyone please has a solution.
iMac 27″ 5K, macOS 11.2