I don't care for actually using mail app, I use mostly the gmail interface and mail app just for offline, for quickly reading and eventually replying.

Everything is working fine, I think I've followed every guide out there... Here's a great one. But I could find nothing about avoiding redundancy.

Well, I can manually do that either by using POP or by checking off most of my labels out of IMAP. But I do use a lot of labels and I often label messages with more than 1 label. And I want them on mail app.

Is there anyway to make it keep just 1 copy of repeated messages? Maybe there's a message id or checksum that could be used...

If there isn't a way to do it, be assured I still prefer having the extra messages and "wasting" space rather than not having any.

edit:

I've came across many solutions for finding duplicate files, but they just delete the files. That just make things worst: Mail will just sync it all again.

I've realized it's probably better to keep two accounts setup, POP for backup and IMAP for everything else with removing the "All Mail" from it. That's because if the "All Mail" on the server is deleted for any reason, my "All Mail" local will also get deleted, while POP will keep all files regardless of the server. This doesn't solve the redundancy issue at all, but it doesn't create any new issue as well, and I can even use the search properly, without duplicated results, if I search just on the POP. So it helps optimizing a little bit.

But I still think the best way to solve this issue would be having something such as aamann's Mail Scripts tweaked to hardlinking the duplicates rather than deleting, and optimized to not need to scan everything every time. I'm trying to contact him and see what we can do.

At any pace, I'm still looking for an answer!