Email, Messaging, & Video Calls Email How to Edit Received Email Messages in Mozilla Thunderbird by Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated on July 21, 2019 Email Yahoo! Mail Gmail Tweet Share Email Exceptions are always good to prove the rule. For this to work the rule, of course, has to be lax enough to allow exceptions. Why Edit Received Emails? Take the emails you receive, for example. Usually, you do not want to edit them at any cost. You want them to be safe, secure, and backed up. But if email is a thesaurus of data and some of that data changes, the emails may have to change, too. You can forward the original message to yourself with an addendum or simply reply to add a new data point to the thread. Usually, this is the ideal solution. But there are, you guessed it, exceptions. For some data — usernames, for example — it can make sense simply to edit the original message. In Mozilla Thunderbird, this is surprisingly easy. Edit Received Email Messages in Mozilla Thunderbird Using "Drafts" To edit a message you have received in Mozilla Thunderbird: Copy the message from its current location to the Drafts folder under Local Folders.Open that Drafts folder.Double-click the desired message in the Drafts folder.Do all the editing necessary.Editing the draft in this manner puts your email address instead of the original senders in the From: line. You can add a Reply-To: header by clicking on an empty address field and selecting Reply-To: from the drop-down menu. Then put the original sender in the Reply-To: field.Click the Save button.Move the message back to the location of the original copy. Edit Received Email Messages in Mozilla Thunderbird by Editing the Source To edit any message freely in Mozilla Thunderbird: Make sure Mozilla Thunderbird is not running.Go to your Mozilla Thunderbird profile directory.Dig down into the Mail or ImapMail and then the desired account's folder or the general Local Folders directory.Open the extension-less file corresponding to the Mozilla Thunderbird folder in which the message you want to edit is located in a plain text editor such as Notepad or TextEdit.You may have to open further ".sbd" directories to reach sub-folders.Make sure you do not open the identically named file with a ".msf" extension instead.Search for the message you want to edit and make the desired changes.Close the text editor saving the file.Open Mozilla Thunderbird.