MacOS – Mavericks Login Screen Mirrored on 2nd Monitor

displaymacbook promacos

I recently had to erase and restore my mac as it developed a terrible hard drive failure, and ever since I've had odd behaviour (already posted one other question today). For some reason the Login screen is mirrored on both my monitors and annoyingly this changes the resolution and aspect ratio shown on the MacBook, I really don't like it, and it's never done this before. It also creates a strange animation as the screen logs in which I fins even more annoying. Before the second monitor would show the background of the login screen but certainly would not effect the resolution of the main screen or be mirrored. What's going on there?

Thanks,
Mike

Two screenshots, one of the displays and a profile error which I can't help but feel is also a side effect of the issue I had. enter image description here

Best Answer

Pressing ⌘+F1 is the shortcut for switching between mirrored (same thing on both displays) and extended desktop (each display is independent) modes.

Pressing that while at the login screen should sort your problem.

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HiDPI on external monitor (Dell u2515h) with Macbook Pro

I encountered the very same problem while setting HiDPI mode for my Macbook Pro with SwitchResX. As the HiDPI resolutions didn't fit, I made my own ones.

Here's how it goes:

Follow the instructions on SwitchResX's website on how to temporarily disable "System Integrity Protection"
On the SwitchResX panel for the DELL screen, go to the "Custom Resolutions" tab and create your desired resolutions under the "Scaled resolution" category.
The pixels x lines you scale to are 2 times the "feeling" you want to get, e.g. 3840 x 2160 for a Full HD (1920 x 1080) feeling.

Disabling the SIP made the 720p resolution you mentioned work for me as well.

MacOS – rMBP – El Capitan – External monitor blurry

There's a Ruby script here:

https://gist.github.com/bastibense/6549835

#!/usr/bin/ruby
# Create display override file to force Mac OS X to use RGB mode for Display
# see http://embdev.net/topic/284710
# 
# Update 2013-06-24: added -w0 option to prevent truncated lines

require 'base64'

data=`ioreg -l -w0 -d0 -r -c AppleDisplay`

edid_hex=data.match(/IODisplayEDID.*?<([a-z0-9]+)>/i)[1]
vendorid=data.match(/DisplayVendorID.*?([0-9]+)/i)[1].to_i
productid=data.match(/DisplayProductID.*?([0-9]+)/i)[1].to_i

puts "found display: vendorid #{vendorid}, productid #{productid}, EDID:\n#{edid_hex}"

bytes=edid_hex.scan(/../).map{|x|Integer("0x#{x}")}.flatten

puts "Setting color support to RGB 4:4:4 only"
bytes[24] &= ~(0b11000)

puts "Number of extension blocks: #{bytes[126]}"
puts "removing extension block"
bytes = bytes[0..127]
bytes[126] = 0

bytes[127] = (0x100-(bytes[0..126].reduce(:+) % 256)) % 256
puts 
puts "Recalculated checksum: 0x%x" % bytes[127]
puts "new EDID:\n#{bytes.map{|b|"%02X"%b}.join}"

Dir.mkdir("DisplayVendorID-%x" % vendorid) rescue nil
f = File.open("DisplayVendorID-%x/DisplayProductID-%x" % [vendorid, productid], 'w')
f.write '<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">'
f.write "
<dict>
  <key>DisplayProductName</key>
  <string>Display with forced RGB mode (EDID override)</string>
  <key>IODisplayEDID</key>
  <data>#{Base64.encode64(bytes.pack('C*'))}</data>
  <key>DisplayVendorID</key>
  <integer>#{vendorid}</integer>
  <key>DisplayProductID</key>
  <integer>#{productid}</integer>
</dict>
</plist>"
f.close

You'll have to run it in El Capitan's rootless mode for it to work.

Best Answer

Related Solutions

HiDPI on external monitor (Dell u2515h) with Macbook Pro

MacOS – rMBP – El Capitan – External monitor blurry

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