MacBook Pro Retina and Windows 8
Sounds funny, but Control Panel only works in user mode, but the .exe file is marked to require Admin rights.

Follow this guide and it will work (trust me).


Start Notepad and paste the following (see ** comment below):


  runas /trustlevel:0x20000 "C:\Windows\System32\AppleControlPanel.exe"

Save the file as "BootCampControlPanel.cmd".
Create a shortcut to this file and save it in the start menu or on your desktop.
Right click the shortcut file. Select properties. Click "Advance..." and check "Run as administrator".
Use this shortcut to start the Control Panel (the icon tray icon still does not work)


So basically we run a Command Prompt in Admin mode, and use this to start the applecontrolpanel.exe in user mode (sounds weird I know, but it works).

** 0x20000 might be different on your machine. From a command prompt run "runas /showtrustlevels" and use the hex number for (Basic User).