The folder Library/StartUpItems is empty Under System Preferences / Users &amp; Groups / Login Items I can see all of the items that I've selected to launch at startup, but the folder,  Library/StartUpItems is empty.

Where can I see these items?
The file the preference pane loads the list of items from is:

~/Library/Preferences/com.apple.loginitems.plist

It is a binary file. You can use Xcode to open it.

For example, if you add iPhoto to your login items:



your com.apple.loginitems.plist will look similar to this: