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Advanced Remove Duplicates

Attention! Important!

Advanced Remove Duplicates is not maintained anymore. There exists another plugin that does exactly the same and is way better: Remove Duplicate Messages (Alternate)

What is it doing?

When importing messages from other mail-programs is could happen that some massages are imported twice. Also when disabling the "leave mail on server"-function its possible that you get hundrets of "new" mails you allready downloaded and that are now twice in your inbox.
Here Advanced Remove Duplicates (ARD) will help you. ARD will search for duplicate mails and will move them in the trash

How does is work?

Simply select "Delete Duplicate Messages" from the context-menu of the folder. Now all duplicate mails will be moved to the trash. Have a short look on the deleted mails to be on the safe side.

Whitch options are there?

In the options-dialog of ARD the following settings can be made:

  • Compare-Method
    • Text-Match
    • Message-ID

Compare-Method

Text-Match

In Text-Match-Mode mails are compared on the following points:

  • Subject
  • Date
  • Author
  • Size
  • Recipients
  • CC-List
  • Number of Lines
  • Message-ID

Only if all points do match a mail will be recognized as a duplicate. This gurantees a hundret percent match. But some mails that are damaged by different import-functions (i.e. addinional blank lines at the end) will not be recognized as duplicates. Duplicate mails with different dates will missed too.

Message-ID

Here is the point where the Message-ID comes into play. Every (better: nearly every(see below)) mail gets an ID by the mail-server written in the mail-header. This ID has to be unique for at least two years. With the help of this ID, newsreader for example are able to detect whether they have downloaded this mail allready. But there are some problems: Some mailserver do not append a Message-ID to any mail, other append the same Message-ID all the time. Due to this the Message-ID is not he best thing to detect duplicate mails. 

The right mix

The second problem can be solved by the text-match-method. The Message-ID is also included but not exclusively. If there is no problem about repeatedly used Message-IDs the combination of both methods is very usefull. Here primarily the Message-ID will be compared. But if the ID is invalid or not existing text-match-method will be used.

Please note!

One important thing about ARD is, that it always moves duplicate messages to the trash of the account the folder belogs to. Due to that you should empty the trash before using ARD. Also it is not possible to scan the trash it self.
I did not test IMAP but it should work without problems.

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