Summary

I have just installed Minecraft on my rather new iMac (didn't have time to play since months due to work). Attempted to create a new world, single player only, and noticed the same symptoms that occur when a server is having a heavy load. Checked the logs, and I saw, that it has thread warns, that it can't "keep up", as seen described in the Environments field of this issue.

Description

I can't provide decent repro-steps, since all I have to do on my machine is to start a new game, or load an existing one.
On Load the game misplaces my character mostly underground, except for game-starts when I'm on great heights.

UPDATE : I can describe one additional symptom. The create world & load world actions take an unusually big amount of time.

Sidenotes

• I have annotated the issue as private because of the sensitive user & local machine information it contains. Please handle it with confidentiality.
• My machine has great horsepower for software engineering purposes mainly. If it's capable of local cloud SOA virtualization without pain, it should work for Minecraft as well.