Find/erase duplicate emails?

[Yumunum]

On Lion Mail, I have my Gmail account and iCloud account. While trying to move all of my Gmail messages to iCloud I've accidentally made a lot of copies, in random places. In the end, I want to just have one version of each message on my iCloud account. I notice that if I go to a copy of a single message, there's a "show duplicates" button to the right. It shows me the duplicates. But I can't do this thing one by one... Is there a way to view ALL of my duplicates at once, for mass deletion? I tried the popular "Mail Scripts" but I get this error message :/

Any ideas? Surely this has happened to someone else, too

 

[Warbitrary]

I would love to find an answer to your question!

I spent many hours trying to find out why I had emails missing in Lion after upgrading from Snow Leopard. It turns out Lion combines 2 identical email files into one message, while Snow Leopard leaves them separate. This make it appear as if I "lost" email.

I've look into Smart Mailbox rules, menu items, Mail Help files, and nowhere is this new duplicate functionality documented. It seems incredibly dumb to hide it, since it confuses users, who might conclude, like me, that they "lost" email.