Here is a problem that has plagued some copies of Windows 10 after the problematic 1809 (Fall 2018) update. After every reboot, your display resets to 1024×768. This problem may affect other versions of Windows too, but this happened to multiple customers after the 1809 update. All were using Intel CPU’s and HP laptops, but it is not a HP or Intel issue. Here are steps you should take to fix it.
- Try the obvious first. Make sure the video card itself is not bad or someone accidentally lowered the resolution or the monitor is not bad. Increase the resolution to the maximum and reboot to test. If you have trouble with the monitor’s known resolution, try another monitor if possible.
- Run msconfig command. Under the Boot tab you will a section that says Boot Options. You want to make sure Base video is not checked. If it is, uncheck it. Click OK and test by rebooting.
- Update the video card driver. If there is no update, roll back your driver. Very very important: When you are asked for the reason you are rolling back, check the box “For another reason” and put “NONE OF YOUR BUSINESS!” in the text box. I am not joking when I say this is very important. Test by rebooting.
- Open regedit and navigate to the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration. There will be several subkeys that may begin with GSM, NOEDID, or SIMULATED. These will be followed by a long hexadecimal number. Each one of these will contain one of more subkeys; always a 00 and sometimes a 01, 02, or higher. For every possible subkey, look for PrimSurfSize.cx, PrimSurfSize.cy, ActiveSize.cx, and ActiveSize.cy. All the .cx entries are for horizontal resolution and all the .cy entries are for vertical. You want to modify every single one of these to your monitor’s maximum resolution. The entries are in hexadecimal, not decimal, so you have to convert. Once you modify every one, test by rebooting. Below are common hexadecimal resolutions:
- f00 (3840) by 870 (2160) – standard 4K HDTV
- 780 (1920) by 438 (1080) – standard HDTV
- 780 (1920) by 4b0 (1200) – high quality HD computer monitors
- 556 (1366) by 300 (768) – standard laptop