My iMac is having issues when returning from sleep mode. For a long time it would return instantly with a button push. Recently, it has started taking forever, to the point where I have to hit the power button for it to return. When it does return, the screen is in black and white, with a progress bar in the center of the screen. When the progress bar fills, the screen blanks, comes back in color, and then takes about 20 seconds before it is responsive.
Any ideas?
Any ideas?