Create message filters in Claws Mail

Jack Wallen
Jul 10, 2009
Updated • Dec 16, 2012

You may have read my recent article about Claws Mail ("Claws Mail: The unsung powerhouse email client."). If you've given it a try you will have noticed just how powerful that email client is. It has a ton of features, and allows for some pretty serious power-user-friendly options.

One of the aspects of Claws Mail that I like more than that of either Thunderbird or Evolution, is the filter tool. I am sure you know that email filters are one of the best means to manage the enormous amount of email coming down the pipe. You can keep SPAM in the trash, filter specific email to specific folders, and take just about any kind of action you need/want.

For many, the Claws Mail filters might not be as simple to use as the standard fare. But that doesn't mean they shouldn't be used.  With this tool, it is just a matter of getting used to a different interface. And that is what this article will help you with.

The tools

There are two ways to create a filter with Claws mail: The easy, less configurable method, or the harder, more configurable method. I will only briefly mention the easy method as that is, well, easy. The second, harder, method is what we will primarily focus on.

The easy method

If you have an email selected, click on the Tools menu and then select "Create Filter Rule". When this new sub-menu pops up you will see four entries:

  • Automatically
  • By From
  • By To
  • By Subject

That will define the condition of the filter automatically for you. You will still have to configure the rest of the filter, but this step automates a portion of the creation.

Now let's take a look at the full creation of a filter by doing things the hard way. I shouldn't scare you off by saying "hard way"'s not really that difficult.

Filter from scratch

Figure 1
Figure 1

When you go to the Configuration menu you will see the Filtering entry. Click that to open up the Filters window (see Figure 1).

As you can see, for the most part, creating a filter is simple. The only aspect that might not be as user-friendly as you are used to is the Conditions and Actions. For these what you have to do is is click the associated Define buttons.  When you do this you will configure the specifics of either the conditions or the action of the filter. Let's take a look at configuring the conditions of a filter. Click the Define button associated with the Conditions. When you do this a new window will open up.

Figure 2
Figure 2

Figure 2 shows a condition already created. What you can not see, from the image, are the included options in the drop down lists. With different types of filters you will have different drop down lists available. The different types of criteria you can select include: Header, Age, Phrase, Flag, Color lables, etc. Say you select the Header from Match Criteria. When you do you can then select:

Name: From this drop down you can then select such familiar items as To, From, Reply To, etc.

Header: This is where you decide if your header Contains or Doesn't Contain. Basically this is a positive or negative match.

Once you have your condition rule set you then click the Add button. If you want you can then create more rules for this one condition. Each condition can have multiple rules and you can move the rules up or down in the chain of command. You can also configure if the rule must meet all or at least one of the rules.

Figure 3
Figure 3

When you are finished with your Condution click OK and it is set. You are now ready to define your Action. Click the Define button associated with Action which will open up a new window (see Figure 3).

This is the easier portion of the setup. What you do is select what action you want to take from the Action dropdown and then select the associated sub-action. The associated action will depend upon which Action you choose. For instance, if you select to Move the mail you will then have to select the Destination folder. If you want to flag the message you will have to select how you want it flagged.

Once you have completed this section click OK. Now, before you finalize the new Filter you have to click the Add button in the main window. If you do not do this your newly created filter is not saved. You will get a warning if you try and then click the Continue Editing and then click the Add button.

Your filter is complete. You can test this by click the Tools menu and selecting Filter All Messages in Folder. If your folder is set up correctly you will see the changes made instantly.

Final thoughts

Claws Mail filtering is a very powerful tool that will allow you to create very helpful filters to keep your Claws Mail organized and free from unwanted email.


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  1. JMGG said on January 19, 2012 at 8:25 am

    You said that Outlook isn’t your main email client, so which is your main one?

    1. BalaC said on January 19, 2012 at 9:42 am

      I think its thunderbird

    2. Martin Brinkmann said on January 19, 2012 at 10:15 am

      It is Mozilla Thunderbird.

  2. Salaam said on September 24, 2012 at 9:52 pm

    Awesome! This actually solved my problem… what a stupid bug.

  3. Claud said on December 19, 2012 at 2:08 am

    If this is the same bug that I’ve encountered, there may be another fix: (1) hover over open Outlook item in Taskbar, cursor up to hover over Outlook window item, and right-click; (2) this should give you Restore / Move / Size / Minimize / Maximize — choose Move or Size; (3) use your cursor keys, going arbitrarily N/S/E/W, to try to move or size the Outlook window back into view. Basically, the app behaves as though it were open in a 0x0 window, or at a location that’s offscreen, and this will frequently work to resize and/or move the window. Don’t forget to close while resized/moved, so that Outlook remembers the size/position for next time.

    1. Lynda said on February 12, 2013 at 3:37 pm

      THANK YOU Claude!!! I could get the main window to launch but could not get any other message window to show on the desktop. You are my hero!!!!

    2. Chad said on November 20, 2018 at 4:24 pm

      Solved my issue! 6 years later and this is still problem…

    3. Ivan X said on January 21, 2021 at 4:50 pm

      Fantastic. Thank you. Size did the trick.

  4. Andrew said on October 26, 2013 at 7:06 am

    This solved my Outlook problem, too. Thank you. :)

  5. Charles said on December 7, 2013 at 7:23 pm

    Thank you so much, this started happening to me today and was causing big problems. You are a life saver, I hope I can help you in some way some day.

  6. garth said on November 7, 2014 at 7:13 pm

    You are a god – thank you!

  7. Faisal said on February 9, 2015 at 10:09 am

    thanks a lot…. work like charm.. :-)

  8. Simon said on March 24, 2015 at 11:36 pm

    Yah…thanks Claude. I’ve been having the same problem and tried all the suggestions…your solution was the answer. It had resized itself to a 0/0 box. Cheers

  9. Olu said on April 14, 2015 at 1:35 pm

    Excellent post. This had me baffled even trying to accurately describe the problem. This fixed it for me.
    Thank you

  10. Coenig said on July 23, 2015 at 7:36 am

    Thanks a lot for the article. Don’t know why it happenend, don’t know how it got fixed, but it was really annoying and now it works :-)

  11. Fali said on January 20, 2016 at 4:19 pm

    Thanks a lot. I was facing this issue from past 3 week. I tried everything but no resolution. The issue was happening intermittently and mainly when I was changing the display of screen ( as i use 2 monitors). The only option i had was to do system restore. But thanks to you.

    1. MIki said on January 10, 2019 at 11:54 am

      I’ve been tried to sole this problem for 12hours. Your comment about changing the display of screen helped me a lot!! Thanks!!

  12. Christina said on January 20, 2016 at 6:14 pm

    Thank you…don’t know why this happened but your instructions helped me fix it. Running Windows 10 and office pro 2007

  13. Oz said on July 22, 2016 at 3:20 pm

    Great tip! Thanks!

  14. Tracy said on September 1, 2016 at 4:48 pm

    Worked for me, too – thank you!!!

  15. shawn said on September 9, 2016 at 10:25 am

    It’s Worked for me, too
    thank you very much!

  16. Jari said on October 31, 2016 at 11:53 am

    I had a similar issue with Outlook 2013 on Windows 10 and this helped me to fix it. Thank you very much!

  17. Michel H said on November 30, 2016 at 11:08 pm

    Thank you so much. Solved!
    Considering you published this in 2012, incredible not been debugged by Microsoft.
    Thank you again. M

  18. Ziad Bitar said on January 9, 2017 at 2:00 am

    This problem was faced by only one user logging to TS 2008 r2 using outlook 2010.The issue was resolved.


  19. Anonymous said on February 15, 2017 at 5:24 pm

    Great tip. Thank you!!!! If it helps, I had to use the Control Key and the arrow keys at the same time to bring my window back into view. Worked like a charm.

  20. Rochelle said on March 6, 2017 at 11:59 am

    Thank you, this worked !!!!

  21. anom1234 said on May 20, 2018 at 11:20 pm

    Man, you are a fucking god. Thanks a lot, what an annoying bug!!

  22. JC said on October 12, 2020 at 2:14 pm

    Awesome, this post solved the issue. Many thanks!

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