When I am playing on my survival world, If I press the Save and Quit to Title button, the game freezes, I can't force quit (apple Q) the game, but it seems to save my progress and then freeze. I play on fullscreen, and have a Late 2009 iMac, if either of those details help at all. A copy of my world is attached, if that helps at all.
What I expected to happen was...:
The game would quit normally, save, and not freeze.
What actually happened was...:
The game saved, and froze up completely. (I can still move my mouse when it's frozen.)
Steps to Reproduce:
1. Play a world.
2. Press Escape.
3. Click "Save and Quit to Title"
4. Congrats! The game is now frozen!
Same thing happening to me. Unmodded client. I thought it was because I was autokilling Guardians with a Command Block and clogging my world with their items but that doesn't appear to be the issue.
Also occurs on the 1.10 pre-release