I've had my iMac about a week and this is my first post. Prior to last week, I ran exclusively in a Win7-64 environment. When I first started my iMac, I created a new user rather than migrate from the Win7 machine. I started setting up my OSX preferences and peripherals as I started learning OSX and Lion. Using a Mini Displayport adapter, I attached my Samsung 26" HDTV as a second display. All of this went well. The next thing I did was to set each display up with a unique background image. The next step was to explore adding desktops. I added several. Each desktop pair was assigned a unique pair of background images. At some point I experimented briefly with choosing a desktop color instead of an image. I defined a lemon yellow background color but did not keep it, reverting to a background image. So far everything was behaving as expected, 4 desktops, 8 unique images. Other things that I experimented with: Unchecked "Show Dashboard as a Space" to eliminate this Adjusted various settings for font size, get info parameters, ttc. Yesterday I installed the 10.7.3 update. On rebooting, the desktop on my primary monitor turned yellow. The secondary monitor and all other desktops retained the assigned images. And it appears the the Desktop image for the Desktop1,primary monitor is there because I can see it through the translucent menu bar. After some research I discovered the Apple had pulled the 10.7.3 update and recommended using the 10.7.3 Client Combo update instead. I D/L'd the Client Combo update and installed that. On reboot, the Yellow went away... for about 15 seconds. But it is back and nothing I know to do seems to fix it. I've eliminated all my desktops but can't eliminate Desktop1. I'm not certain if the yellow background overlay is the result of the Update or some tweak I did to window settings. or some other settings. If anyone has a solution, I would like some help. While we are on the subject of Desktops, when ever I enlarged an application to Full Screen, it always goes to the primary display and the secondary display gets a charcoal pattern and is unusable for anything. Here is a screen shot of my 'yellow screen. You can see bits of the desktop image peaking through the translucent menubar.