FAQ (Frequently Asked Questions)

"The extension isn't working! What's wrong?"

What, exactly, is the problem? Consult one of the specific sub-questions. If none of them fit, please file an issue.

"removedupes says there are no duplicates, but I know there are! I can see them!"

It is almost 100% certain that your messages are not really duplicates. That is, they are to you, but they have slight differences which you're ignoring, but the extension is not configured to ignore. For example: An extra line of white-space at the bottom; or a difference of a few seconds in send time.

To overcome this issue, start gradually removing comparison criteria from your dupe search, until you see duplicates. Then possibly add criteria back - probably in another order than before. Be careful! You don't want to end up removing messages you weren't expecting to remove. If you find out the issue is time resolution, change it in the preferences dialog.

"The extension refuses to search special folders for duplicates."

This is intentional, since there are often messages in such folders which are "structurally duplicate", e.g. an email you sent to a mailing list and its copy that you got from the list. Also, most users do not want to have messages deleted (semi-)automatically from the Send or Drafts folders etc.

You can disable this precaution in the preferences dialog, and make the search consider all folders with no exceptions.

"Nothing happens when I click the Remove Duplicate button or select duplicate removal on the menu"

This may be a bug. Please restart and recheck. If it persists, check the console (Tools | Developer Tools | Error Console) for error messages mentioning the word "removedupes". Copy them.

Finally, file a bug report, and make sure to include all the information you gathered, your versions of Thunderbird and the extensions, etc.

"How do set the extension's preferences, like comparison criteria?"

In one of three ways:

1. If you customize your toolbar, you can add a Remove Duplicates Menu Button - both for triggering the extension's functionality and for setting the different comparison criteria.
2. All extension preferences (essentially) are accessible on the Menus : Tools | Add-On Preferences | Remove Duplicate Messages (Alternate); that's with Thunderbird 68. With earlier versions, you may need to visit Tools | Add-Ons, selected the extensions tab, find "Remove Duplicate Messages (Alternate)", and possibly right-click to get access to the preferences dialog.
3. You can use the general Config Editor, accessible through Thunderbird's general preferences dialog, in the Advanced section (a button says "Config Editor").

Versions and compatibility

"Which mail client applications are supported?"

• Thunderbird: guaranteed to be supported (see also below).
• Seamonkey: Used to be supported - but only up to 0.4.x releases. Version 0.5 no longer Supports Seamonkey.
• Postbox: not supported.

"Is the extension compatible with my version of Thunderbird?"

Thunderbird has been changing dramatically in recent years, and the different versions of the extension are compatible with different ranges of Thunderbird versions. At any given time, the latest release of the ectension should be compatible with the latest release of Thunderbird; but as released are made, allow for a short period of time before the extension is updated to be compatible with the new release.

"I have a question not covered by this FAQ..."

Please search the issues page of this repository, to check if it's already been reported. If not, file a new issue. If you'd like to tell me (the author) something about the extension and/or the state of Thunderbird in general - you can write me.