Mail.app Conversation/Threading issues like RES: RES: RES: When using Gmail on Apple's mail, the conversations/threads are not being grouped properly when the subject field of the messages starts having many prefixes "RES" in the subject.

Some email clients (e.g. Mail in iPad), adds a "RE:" or "RES:" prefix every time when a message is replied. This, causes some subject fields having something like: "RES: RES: RES: RES: Original Subject".

When this situation happens, the conversations in Mail.app apparently break, that is, one email (or more) that should be grouped to a conversation is displayed as a different conversation.

This is an example that causes problem for me:


I send a message with subject "Test"
I receive a reply with subject (sent from other email client) "RES: Test"
I reply again (using Mail), then the subject becomes: "Re: RES: Test"
I receive a reply with subject (sent from other email client), and the subject now comes as: "RES: RES: Test"


At this point, I've got 3 different conversations where this should be grouped as one.
If I open Gmail, the conversation works perfectly, but in Mail it doesn't.
Is there anything I can do about it?

Using Mail.app 6.5
The threading does happen based on subject.  Re: is ignored; so Re: Re: Re: foo is the same as foo, and the same as Re: Re: foo.  That's why it works.

What is RES:?  Is it Re: in a different language?  That's why it's breaking - because RES is not being ignored and therefore looks like a different subject.

The person you're conversing with needs to use Re:, not RES:.  RES: may be inserted automatically by their email client; in which case you may need to find a different way to group the emails, perhaps by sender.

There are tools that can help, though.  With MailTags (http://www.indev.ca/MailTags.html) you can group/organize your email much differently or simply use the subject renaming feature.  With MailActOn (http://www.indev.ca/MailActOn.html) you can match a rule that moves the email to a specific folder ignoring the "RES" part, etc.  There are many options.

No, I am not affiliated with Indev, I just use and love their products.  :-)
Best of luck.