macOS defaults

Appearance

Show Subject Field ​

Show the subject field which appears above the iMessage/Text Message field in Messages. Text entered in the subject field will be sent in bold (unless there is no text in the iMessage/Text Message field; in this case, the text in the subject field will be sent without the bold effect).

  • Tested on macOS:
    • Sonoma
  • Parameter type: bool

Set to true ​

Show the subject field in Messages

bash
defaults write com.apple.MobileSMS "MMSShowSubject" -bool "true" && killall Messages

Messages app with subject field showing

Set to false (default value) ​

Hide the subject field in Messages

bash
defaults write com.apple.MobileSMS "MMSShowSubject" -bool "false" && killall Messages

Messages app with subject field hidden

Read current value ​

bash
defaults read com.apple.MobileSMS "MMSShowSubject"

Reset to default value ​

bash
defaults delete com.apple.MobileSMS "MMSShowSubject" && killall Messages