open up a Terminal window, and type
ps -x |grep -i python
Do you see dozens and dozens of processes named (python)? Then you’ll probably be interested in the discussion here.
This turns out to be due to a bug in XCode 2.3’s distributed builds functionality. There’s this sctwistd process that gets launched at startup, and every time you log in and out (even switching to another user counts), it spawns off a couple of python processes that get orphaned from their parent. These zombies accumulate over time, eventually leaving your Mac unable to launch any more programs.
Long story short, if you don’t use dedicated network builders and you don’t want to fill up your process table with Zombie Python Processes from Hell, perform these commands in a Terminal window, then reboot:
sudo launchctl unload -w com.apple.dnbobserver.plist
Now if I can just figure out why Nikon View Monitor is being launched, even though I don’t even use Nikon View anymore, I’ll be a happy camper. I just don’t like running software that I don’t need.