Q: Messages not working after OS X Update
After the December 28th Update for OS X I have been unable to open messages on my Mac. I am simply greeted with a notification saying "Messages cannot be opened because of a problem" Everything on my computer is up to date as far as I am aware and none of my friends nor my Dad have been able to figure out why this happened.
MacBook Pro, OS X El Capitan (10.11.2)
Posted on Jan 2, 2016 4:59 PM
Might be a corrupt .plist.
Do a backup, preferably 2 backups on 2 separate drives.
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 and Ralph Johns (UK) for some information contained in this.
Posted on Jan 3, 2016 8:26 AM



