Method #1 for Finding and Searching iChat and iMessage Messages on a Mac
Here are two methods to search all of your archived Mac messages at once. Let’s say you want to search all of the text messages that you have received on your Mac via Messages (formerly iChat), sent using Apple’s iMessage system, because you know someone sent you some information via chat messages, but you can’t remember who, or you can remember who but it was so long ago that scrolling back on your iPhone or in your Mac’s Messages chat window would take forever.