Rated 5 out of 5 stars

by nothing on Nov. 30, 2020 · permalink

Try this if it didn't work :
(1) From Menu Bar, choose Tools / Add-on Options / Remove Duplicate Messages
*** If your Menu Bar is hidden, click on the Three Lines Icon on the right side of the Search Bar, then choose Customize and check the Menu Bar
(2) Go to Message Comparison tab, and try to change the elements used as the comparison criteria, and then click OK
*** In my case, I unchecked the Size element
(3) Run the Remove Duplicate action