Whenever I start up minecraft it will freeze anytime between 1 second to 3 minutes. When it freezes all I can do is force shutdown manually, and I can't find anything that says something is wrong. l I have a unchanged minecraft 1.6.2 but this started when 1.6.1 came out. It hasn't happened any other computer I have. I have looked around for tutorials on how to fix this and none have worked. I've reset everything I can, deleted everything in minecraft, re-installed java, taken it to the apple store to see if it was the computer! I really need some help! Here is some information on my mac if it helps!
iMac
21.5-inch, Mid 2011 Processor 2.5 GHz Intel Core i5 Memory 8 GB 1333 MHz DDR3, Graphics AMD Radeon HD 6750M 512 MB Software OS X 10.8.4 (12E55)
Have you already tried to delete/move the .minecraft folder out of your appdata?
I've deleted it and let it re-download so many times I can't remember how many time it was. Also on a mac it isn't .minecraft it's just called minecraft.
iMac
21.5-inch, Mid 2011
Processor 2.5 GHz Intel Core i5
Memory 8 GB 1333 MHz DDR3,
Graphics AMD Radeon HD 6750M 512 MB
Software OS X 10.8.4 (12E55)