Enable iMessage (Messages) Subject Field in macOS Big Sur through Sonoma

macos-messages-subject-field.md

Want the Subject field (for bold iMessages) in macOS’ Messages app?

1. Quit Messages
2. Open Terminal
3. Run defaults write com.apple.MobileSMS MMSShowSubject 1
4. Start Messages

This worked for me on a fresh install of macOS 14.1.1 (23B81) (new Mac mini).

Note: On modern versions of macOS, you must enable Privacy & Security > Full Disk Access for your Terminal app in System Settings.

Very weird @2xsaiko, could you post / DM me your plist so I can copy that in and see if that works?

https://gist.github.com/2xsaiko/3604038825dc1118b81eda7c8f0ba1b3

@jbburf @2xsaiko can either of you identify the different between your two plists? It might be helpful for others and I can update the instructions if needed.

I mean that's really it, I just added it to the top level dict as I said. To the end that is, after I ran Messages again it rewrote the file and placed it somewhere in the middle, that's why it's no longer at the end in the paste.

It's probably safer to tell people to edit it with Xcode instead, there's no risk of messing up the file that way...

@jbburf I just figured out that on modern versions of macOS, you must enable Privacy & Security > Full Disk Access for your Terminal app in System Settings and then it will work. I am not sure if that is what you were running into, but worth a shot if you never got it working.