Im still desparately trying to configure & clean emails after extricating from outlook, but synced to Yahoo email which has further helped make a mess of them.
I am afraid to run it - there is little on this topic or getting HELP at all. i have EmClient v 8
You can choose which folders to include in the search, so if you just want to check the Inbox, select that folder.
You can also specify in the second option, if the duplicates should be in the same folder. This will search all the folders you specified, but if the message and its duplicate are not in the same folder, there will be no action on them.
If you are uncertain, rather than deleting the duplicates, move them to a custom folder.
Once you are happy with the outcome, you can delete the custom folder.