MailFollowUp mail plugin adds "Follow Up" items to the Message and contextual menus (and optionally a toolbar button) of Apple's Mail application that allows you to compose (and then send) a quoted version of the original message to all of the original recipients, keeping the To, Cc and Bcc addresses exactly as they appeared in the original message.


Author's Note: As of 2.0, I am providing the plugin only. I cannot provide an installer, and you must perform a manual installation as described below.
You might need to provide Full Disk Access for the Terminal application to successfully use the following commands. You should remove this elevated Terminal permission after you have issued the commands.

Also, as of macOS 10.4.2/Mojave, Apple has incorporated a new Mail plugin management scheme. After you install any plugin (including mine) you must enable them from within Mail per steps 5–9 below.

1. Quit the Mail application.
2. Download (see above), expand, and mount the MailFollowUp disk image.
3. Drag MailFollowUp.mailbundle to ~/Library/Mail/Bundles/ ("~"means a user's home directory). You might need to create the Bundles folder if it does not already exist.
4. If you have never used another Mail bundle, you will need to run two special commands in the Terminal application (omit the % prompt).
% defaults write ~/Library/Containers/com.apple.mail/Data/Library/Preferences/com.apple.mail.plist EnableBundles -bool true
% defaults write ~/Library/Containers/com.apple.mail/Data/Library/Preferences/com.apple.mail.plist BundleCompatibilityVersion 4
5. Launch the Mail application again.
6. Select “Preferences…” from the Mail menu.
7. In the General tab click the "Manage Plug-Ins…” button near the bottom left.
8. Select (check the box for) each plugin that you want to use.
9. Click the "Apply and Restart Mail” button.

After Mail relaunches the plugin(s) should be available, assuming all else is correct/well.


MailFollowUp is freeware. However, if you enjoy using MailFollowUp and would like to help support its development, please consider making a donation.

Requirements:
OS X 10.14.2+
Apple Mail 11+
64-bit Intel

Also available are:
Version 1.9 for OS X 10.13
Version 1.8.4 for OS X 10.12.4
Version 1.8 for OS X 10.11
Version 1.7.3 for OS X 10.10
Version 1.6.5 for OS X 10.9
Version 1.5.8 for OS X 10.8
Version 1.5.4 for OS X 10.7
Version 1.4.5 for OS X 10.6
Version 1.3.1 for OS X 10.5
Version 1.1 for OS X 10.4