Synaptic Package Manager doesn't launch from the Application Menu

You can fix it by following:

1. Open terminal (ctrl+alt+T) and execute:

   gksudo gedit /usr/share/applications/synaptic.desktop
   

   If gksudo is not installed, you can just install it. It's provided by the gksu package.

   (Or you can run sudo -H gedit instead. But avoid sudo gedit).

2. Change line Exec=synaptic-pkexec to Exec=gksudo synaptic.

3. Save file and close text editor.