Problems Identified:

Zimbra Desktop only has the US dictionary installed. This means that it corrects UK spellings to the US even after the UK locale has been specified as the language in Desktop preferences. The Zimbra Wiki note was incomplete and did not actually work.


  1. Change the Language to English United Kingdom in Zimbra Desktop Preferences
  2. Replace the en-US.dic and en-US.aff files with the UK ones and edit the configuration file user.js to reflect the change.
    We had to deal with two operating systems, MAC Sierra and Windows 10 Anniversary edition. In both cases, the Wiki solution did not work because of permissions and incomplete instructions.
  3. Location of the Files
    • Windows 10
    The dictionary files are located in:
    C:\Program Files\Zimbra\Zimbra Desktop\win64\prism\xulrunner\dictionariesThe configuration file is found in:
    C:\Program Files\Zimbra\Zimbra Desktop\data\profile

    • MAC Sierra
    The dictionary files are located in:
    /applications/zimbra Desktop/macos/prism/

    The way you see this directory level is to navigate to the and then right click and “open package contents”. You will then see the /Contents/Frameworks/XUL.framework/dictionaries  folder.

    The configuration file is found in:
    /applications/zimbra desktop/data/profile

  4. Permissions
    In MAC sierra we found we could not copy the en-GB.dic or en-GB.aff files into the folder using copy and paste. We opened two Finder windows, one showing the dictionaries folder and the other showing the expanded download folder with the two en-GB files in it. We then dragged them over. We needed to enter the user’s password again to gain administrator access to complete the process. Drag and drop then succeeded.In both Windows 10 and MAC Sierra we could not edit the user.js file directly. We had to copy it, edit the copy then drag the copy it back to the folder location. Once the copy was there we deleted the original user.js and renamed the copy to user.js As a precaution, we made two copies of the user.js file!

The Solution Steps are as follows:

We have set out seven steps to complete this process below.

  1. Change the Language in Zimbra Desktop Preferences
    Click Preferences and General.
  2. Close Zimbra Desktop
    In Windows 10 you have to actually quit it by right clicking the icon on the taskbar near the clock and selecting quit. Just clicking the X in the Zimbra Desktop window does not close it down.
    On the MAC you close the icon on the taskbar. Again closing the desktop window does not close the application.
  3. Download the UK dictionaries from Zimbra
    The UK dictionaries are found here:
    Once the zip file is downloaded, expand it to reveal the two files en-GB.dic and en-GB.aff
    Then copy them somewhere easy to find!
  4. Copy the expanded dictionary files to the relevant locations.
    Please see solutions 2 & 3 in this article.
    • Windows 10
    The dictionary files are located in:
    C:\Program Files\Zimbra\Zimbra Desktop\win64\prism\xulrunner\dictionaries

    • MAC Sierra
    The dictionary files are located in:

  5. Delete the en-US.dic and en-US.aff files.
    It is very important to delete the original en-Us.dic and en-US.aff files so that only the en-GB.dic and en-GB.aff files remain in the dictionaries folder.
  6. Amend the user.js file to reflect the en-GB locale for the dictionaries.
    Please see solution 3 in this article. You cannot edit the user.js file directly. Copy it first.In the copied user.js file edit the line to show:
    user_pref(“spellchecker.dictionary”, “en-GB”);
    Save the file and check your change has taken by opening it again. Now copy it back to the profile directory and delete the original user.js file.
    Rename the copied one to user.js
  7. Restart Zimbra Desktop
    We actually restarted the machine because we were never really sure that Zimbra Desktop had closed. But once done we tested color and endeavor and all was well!