the solution!
Hello world,
Apple told me the solution: you must delete your account's cache files. this solutions works perfectecly on my macbook pro 13 mid-2012.
in the finder : go to your account folder, find the "Preferences" folder and empty it.
After go to Macintosh HD/Library/Preferences/"System Configuration" and empty it.
Clean the bean and reboot your Mac
You will loose all your account preferences, your different desktops, JAVA and X11 (Maybe) but your mac will go faster!!!!
Sorry for my English, I'm French. 🙂