Apple Studio Display 17: Only 640 by 480 Resolution Is Available

Symptom

When you turn on the computer, the display defaults to a 640 by 480 resolution. No other resolutions are available in the Monitors control panel. Resetting the computer's PRAM or dragging the Display preferences file to the Trash temporarily restores all resolutions, but the issue recurs when you restart the computer.

Solution

1. Make sure your computer is using Mac OS 9.2 or later. If not, download and install the Mac OS 9.2.1 Update or later. Once Mac OS 9.2 or later is installed, continue with the next steps.
2. Press the display's power button to turn it off.
3. Unplug the display's power cord.
4. Plug in the display's power cord.
5. Turn on the display.

If you cannot upgrade to Mac OS 9.2 or later, you can restore the resolutions by turning off the display data channel (DDC) feature. Follow these steps:

1. Press the On-Screen Display (OSD) Enter button located on the left side of the display. The Basic Adjustments menu appears.
2. Use the left or right arrow buttons to select the ETC icon.
3. Press the Enter button. The choices On or Off appear.
4. Use the left or right arrow buttons to select the Off icon.
5. Press the Exit button to leave the OSD.

The DDC feature is now turned off and the resolutions should appear in the Monitors control panel.