you will find it in System Preferences > Universal Access and then the Seeing Tab.
My desktop picture/entire screen have been covered with a white screen/background; when I first start my machine up my desktop picture appears for several seconds and then is overlaid with the white background.
If I shut down, my desktop appears for a few seconds before quitting.
What could have caused this anomaly and how can I fix it?
I need to transfer some files from my external hard drive to my machine but can't since my ext. HD doesn't show on my desktop because of the white background.

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