With the latest OSX Mavericks 10.9 release, Wireshark refuse to open and complain about X11.
First, make sure you have the latest XQuartz installed. It can be found at :
http://xquartz.macosforge.org/
(Make sure to logoff/login again to your session once you installed it.)
Then, if you attempt to open up Wireshark, you’ll end up with a message saying Wireshark cannot find X11 :
Where is X11?
Just select XQuartz manually here :
/Applications/Utilities/XQuartz.app/Contents/MacOS/X11
You might see the Wireshark icon in your Dock, however the window might not be visible yet. Close the program.
Open XQuartz and type the following command :
/Applications/Wireshark.app/Contents/MacOS/Wireshark
Wireshark should open normally from now.