I just found a plugin for Evolution to remove duplicate emails. Thanks, Carlos Garnacho! By the way, any change of moving this to GNOME’s FTP server, or maybe inside Evolution? I’d be more than happy to translate it, in exchange 
By the way, thanks for the tip, Juha K. Siltala!
Last time somebody tried it, they faced some problems. I will look into this, and if all goes well, it will be in Trunk soon
Thanks Leonardo! I’m glad you like it
, it can be quite useful at times, it definitely was for me.
Sankar: I think the problems were mostly caused by having a versioned evolution-plugin-2.x.pc file, which forced external plugins to follow up on evolution development or fail to build for more recent evolution versions. Since that file isn’t versioned anymore, everything has been smooth sailing
I must say I’ve also found this plugin a win. I applied it to a virtual folder that contained everything and found 20,000+ duplicates, I didn’t delete anything until I was a bit more certain that they were duplicates. And yes they all where. I run this from time to time as sometimes when sorting mail or using offlineimap I get duplicates. No longer a problem thanks to this plugin.