how to set up 2 iMessage account on one mac
My wife and I have each our own imessage account for our own ipad and iphone, but we share th same imac at home.
Every time I receive an imessage, it appears on the mac and when she send one, I have it automatically on my devices ( and it appears that it was sent by me) because my apple ID is the main one registered in our MAC.
How can I set up both imesssage accounr on the mac so that she can choose who is sending the message? Is there a way to have two imessage box open, one for each of us?
Regards
iMac (27-inch, Late 2012), OS X Mavericks (10.9)