How do I delete duplicate emails in Mail?

Highlight them and press the delete key.

 

I think the closest you will be able to get is creating specific search criteria so that only those duplicates show up in the result and then you can select them all and delete them. Who knows though, tweaking the search to include every single one could very well take longer than just going through them all.

 

You could try this ; it appears to be updated and maintained.

 

One trick I used when facing this problem was to download and install Mozilla Thunderbird and set it up to check the same account via IMAP. This requires that you move all the messages to the server via IMAP, which can take some time (27,000 messages in my case). Then you can install a plug-in into Thunderbird that automatically locates and eliminates duplicates.

Once everything is cleaned up you can use whatever IMAP capable program you want to manage your mail. Just make sure you use the option to sync messages between the server and client so you can access your mail offline.

 

OP, any idea what caused the 5000 mails to be duplicated in the first place?

 

try this

had the same problem

try this
http://www.mac-forums.com/forums/os...ail-showing-duplicated-incoming-messages.html

 

Mail Scripts works well; you can find it at: http://homepage.mac.com/aamann/Mail_Scripts.html