I've noticed that iMessage doesn't sync on my Mac after the last OS X update. Before that, everything worked fine. After it, nothing. How to fix it? I've tried logging out and restarting and logging out of all devices from iCloud and iMessage and restarting and so on and nothing works. So, thoughts? What am I missing? Apropos of nothing, or maybe it's linked, in Airdrop my Mac won't recognize my iPad under "My Contacts" but if I set the iPad to "everyone" then it does; this is also vice versa (i.e. the iPad doesn't recognize the Mac for Airdrop unless I set the Mac to "everyone.").