TOPIC
This document contains the answers to frequently asked questions (FAQ) about monitor resolution switching during the startup process.
DISCUSSION
1. Question: I have set my monitor's resolution to 1024 x 768. When I start my computer, the monitor is set to 640 x 480, then switches during the startup process to my selected resolution. Why does this happen? Answer: As long as the Macintosh displays your preferred resolution when the Finder finishes loading, this is normal. This behavior varies from Macintosh to Macintosh depending on the CPU, video card, software versions, and monitor being used. If the preferred resolution setting is not available on the display after the computer has completed booting, you may not have the display configured correctly. If your computer and display have ADB or USB connections, verify the display is connected properly, and ensure the latest version of Apple Displays software is installed. There are a number of variables that determine the display resolution setting at startup: On older computers, there is a PRAM value used to set the resolution read at startup by the video driver residing in ROM. Newer versions of Apple Displays Software rely on a preference stored on the hard drive to set this resolution instead of the PRAM setting. This preference is read during the startup sequence, and is applied either during startup, or when the Finder loads, depending on the video controller. On some computers, you can use the traditional Monitor control panel to set the PRAM setting to the resolution of your choice for startup. This is not the case with all Macintosh computers. Different video cards and built-in video handle resolution preference loading at different times, depending on when the driver for the video card and built-in video is loaded. Some computers and video cards (usually older models) do not recognize multiple scan displays at startup, because the required driver is not built into ROM, and is only loaded when the Apple Displays Software loads. AppleVision/Colorsync models have a unique sense pin setting that, when combined with the ADB connection, tells the computer that it is an AppleVision display. Until the AppleVision extension loads, some computers and video cards will read this sense pin as a standard 13" display since the sense pin algorithm is not yet complete. Therefore, the computer will start up in 640 x 480. After the AppleVision extension loads, the computer will recognize the display properly, and apply the user's preference for resolution setting. Again, depending on which video controller is used, the preference may load during startup, or after startup is complete. 2. Question: When I start my computer with the Shift key held down, it stays in 640 x 480 resolution, and never switches to the resolution I normally use. Why does this happen? Answer: When the system is started with the Shift key down, it will disable the display extension and not load the display preferences. Note: If you are starting your computer with the Shift key held down to troubleshoot a possible software conflict, you can try starting the computer with the space bar held down to open the Extensions Manager. The display will switch to your specified resolution during startup. You can then customize extensions to be loaded. 3. Question: I have installed Mac OS 8.6 on my Power Macintosh G3, and set the display resolution to 1024 x 768. When I start my computer, I notice the resolution starts at 640 x 480, and switches during startup to my selected resolution. When this switch happens, the desktop pattern behind the Mac OS logo disappears, and changes to gray until the Finder loads. I did not notice this behavior under Mac OS 8.5.1. Why is this happening? Answer: The resolution switching is normal behavior as outlined above. The gray desktop pattern is cosmetic, and will not affect the performance of your system. Apple is investigating possible solutions to this temporary loss of the desktop pattern during boot. |
| Document Information | |
| Product Area: | Mac OS System Software |
| Category: | General OS |
| Sub Category: | General Topics |
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