The fix does not stay, guess I'll wait for Apple to releases a fix.
It usually shutdown in 2,3 seconds while I was on Lion. I upgraded to ML recently and this happened.
In launchd-shutdown log, I found this
20006079 com.apple.launchd 1 com.apple.securityd 17 Exit timeout elapsed (20 seconds). Killing
20008561 com.apple.launchd 1 com.apple.coreservices.appleevents 65 Exit timeout elapsed (20 seconds). Killing
Things I have tried but no luck:
- I have reset PRAM
- clear kext-cache. it works at first shutdown only though.
Any idea how to fix this!?

ps -axfrom the Terminal (to list all processes running)? – Ben Mordecai Jan 5 at 22:31