Disable read receipt on mac mail, using Macbook Pro OS Sonoma.

ChampM8 wrote:

Yes unfortunately I did apply a command in Terminal but I can't remember exactly what it was and now I wish to disable it.

defaults delete com.apple.mail UserHeaders

If you have added any other custom user headers in the same manner, they will be deleted along with the disposition notification.

There are property lists in your user Library/Preference folder.

They are generally named in the form com.company.program.plist, so look for ones with Mail in the name and open them with a Text Editor. If you find one that contains a key/value pair for UserHeaders, delete that entry.

It is likely in the form:

<key>UserHeaders</key>
<dict>
<string>all of the header text you inserted before</string>
</dict>

I found this suggestion searching the internet for you:

defaults delete ~/Library/Containers/com.apple.mail/Data/Library/Preferences/com.apple.mail.plist UserHeaders

There are property lists in your user Library/Preference folder.

They are generally named in the form com.company.program.plist, so look for ones with Mail in the name and open them with a Text Editor. If you find one that contains a key/value pair for UserHeaders, delete that entry.

It is likely in the form:

<key>UserHeaders</key>
<dict>
<string>all of the header text</string>
</dict>

Mail doesn't send or respond to read receipts natively. You would have had to create a header that adds the disposition status request in Terminal. Did you ever do that?

I don't know why that happened, but yes, you are still sending requests for disposition notifications.

Unfortunately that doesn't help me much. Surely there is more that could be done.

You could hunt around in all of the Mail Plists until you find the UserHeaders entry and delete it manually.