Messages.app only shows replies Mavericks (10.9.5) Messages app is only showing what other people are typing, and not what I am typing! Has anyone else seen/fixed this?
As Buscar noted above, I got an answer to my problem from a very helpful person on the Apple discussion board. You can see the discussion here.

Somehow, this problem is related to permissions, and ACLs. The answer involved checking permissions from the command-line to see if there was a problem, and then resetting the permissions using either the command line, or using the Recovery partition on your Mac.

Use the following command to see if permissions/ACLs are incorrect:

find ~ $TMPDIR.. \( -flags +sappnd,schg,uappnd,uchg -o ! -user $UID -o ! -perm -600 \) 2&gt;&amp;- | wc -l


If you get a number other than 0 back, then there might be a problem. Use the following to repair permissions/ACLs (make a backup first!):

sudo find ~ $TMPDIR.. -exec chflags -h nouchg,nouappnd,noschg,nosappnd {} + -exec chown -h $UID {} + -exec chmod +rw {} + -exec chmod -h -N {} + -type d -exec chmod -h +x {} + 2&gt;&amp;-


Alternatively, you can 'Reset Home Directory Permissions and ACLs' outlined in this Stackexchange post.

I hope this helps someone else out there!