For me, sometimes safari or iTunes won't quit for a very long time (usually a network thing) and the shut down will hang. The second i force quite the "sticky" app it's an immediate shut-down.
Have you tried that? after hitting shut-down, looking and what apps are open, and force quitting to see if any are causing the hang.
Ive had multiple macs in the last two years and some tai awhile to shut down and some don't. Im guessing its the software running at the time. I have yet to have one take 2 minutes to shut down. Most of the time its about 1 minute on the slow end.
I don't have an rMBP but I did have very slow shutdowns too at one point so I searched around for a solution until I tried this solution and it worked for me. Try it out:
In terminal, enter:
Code:
rm ~/Library/Preferences/com.apple.desktop.plist
This removes the desktop plist file (don't worry as it will be regenerated shortly.)
Then enter:
Code:
killall Dock
Then try to shutdown. For me, shutdown was almost instanaeous compared to the two to three minutes I was first getting which was a huge difference. Hopefully this will work for you too. 🙂