Hi, i use a mac pro 3.1 (early 2008) with an ATI HD 5770 Graphic Card and two Samsung Syncmaster 226BW Displays. Evrything works perfect, except i only can use on ColorSync Profile. 1 Display is connected directly to the Graphics Card DVI Output, the other with a miniDVI to DVI Adapter. when i choose a color Profile on the left Display, the same Profile will be set to the other and vice versa. also only one Display really seams to use (Change) to this color Profile. I´m also not in Mirror Mode ;-) The Systemprofiler shows me both of my Displays under the Graphic Card Tab, but in ColorSync there is only one Syncmaster Display listet. I have installed Snow Leopard now again on an external Firewire Drive and there everything works perfect ! So i think this can not be a Hardware Problem ! I also did a clean install of Mountaion Lion (10.8.0) on another Disk and after the very first reboot, without installing any other Software, the same Problem happens again. There also should not be a Problem with Software which i had installed before. I Think the generally Problem is ColorSync, which only "sees" one of my Monitors under Devices in Mountain Lion. ColorSync under Snow Leopard shows me both Displays under Devices, as it should be. Sadly i don`t know where i can change this information for ColorSync in Mountain Lion. My first Idea was to move the "com.apple.ColorSyncUtility.plist" to the trash and restart, but this also don`t resolved my problem. when i open the "com.apple.ColorSyncUtility.plist" from Mountain Lion with Apples Textedit, i can see the following: while the "com.apple.ColorSyncUtility.plist" from Snow Leopard shows me: I have repaired Permissions many Times and cleaned all Caches with TinkerTool System. Changed all cables and Adapters. Did clean Installs of Snowleopard and Mountaion Lion. A friend of mine installed Mountain Lion yesterday, also on a Mac Pro and with the same Graphic Card and he don`t have any trouble setting different Color Profiles for each Monitor. So this basicly seams not to be a general Mountain Lion Problem, but he also uses two different Displays from different Manufactors, while i use two identical Displays from one Manufactor. I´m thankfull for any information how to fix this because it drives me Nuts !