Messages Freezing - Post Mojave update
I've followed all the guides dumped cache etc etc - Messages hangs when I open it or randomly while typing. This is my workhorse - updated hoping to get a smoother experience - not yet!
SG
I would think that something is using it in the background...Something that itself is not responding.
So, Force Quit it (and all else, if an option), then Retry to open it alone.
Go to the Apple Menu atop the screen > click Force Quit > Select FaceTime > Click the Force Quit button > Reopen it.