HI, you can solve this with 2 methods:
method 1:
Disconnect the second monitor in the installation, after the installation and final configuration connect your second monitor.
Method 2:
Use this information:
Some users might be aware that there has been a great fix using a Ruby script to create a new EDID for your display. This is to fix an issue with some displays and Mac OS whereby it sees the display as a TV screen and is not using RGB mode for it, resulting in a very bad display quality (washed out, fuzzy, pixelated, etc).
The 'old' trick with using the Ruby script and placing the files in .../System/Library/Displays/Contents/Resources/Overrides/ doesn't work any longer, even with SIP disabled as the file system is now mounted read-only. You can mount it read-write but that's a very long-winded and potentially lethal solution.
The easy fix:
download the ruby script: https://gist.github.com/adaugherity/7435890
in terminal, run the script with 'ruby' followed by the script location/name
it will create a folder in your home directory (something like 'DisplayVendorID-XXXX...)
in /Library/ create following new folders: Displays/Contents/Resources/Overrides/
copy the whole folder from step 3 (located in your home folder) to the Overrides folder you created in step 4
reboot
Credits go to: https://www.mathewinkson.com/2013/0...ix-the-picture-quality-of-an-external-monitor for the original solution/follow ups, https://gist.github.com/adaugherity for the forked Ruby patch
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I tried both methods 3 hackintosh pcs, and works fine
