I can't log in into messages

Do a backup.

Quit the application.

Go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J. When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder. Select Library. Then go to Preferences/com.apple.iChat.plist. Move the .plist to your desktop.

Restart the computer, open the application and test. If it works okay, delete the plist from the desktop.

If the application is the same, return the .plist to where you got it from, overwriting the newer one.

If that doesn’t work, repeat the above but delete the com.apple.imagent.plist

Thanks to leonie for some information contained in this.

You are welcome.

Messages – Can’t log in

Messages - Error Processing Registration

Hi,

Open Font Book.

Check the AppleGothic font (it is near the bottom)

It show be active, not Duplicated and should Validate (from the File Menu).

If this does not solve it then use the File Menu > Restore Standard Fonts.

9:17 p.m. Friday; September 11, 2015