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Force RGB mode in Mac OS X to fix the picture quality of an external monitor

I recently bought a MacBook Pro (with ‘Retina’ screen), but when I hooked it up to my Dell U2410 monitor via HDMI cable I was shocked by the poor picture quality. The contrast was all wrong and text was misshapen. No amount of calibration in the monitor or software would fix it.

Short answer: OS X thinks my monitor is a TV, and is using the YCbCr colour space rather than RGB. I had to override an EDID setting to force the RGB colour space, and it is now working correctly.

Long answer: I haven’t owned a Mac for a while and had forgotten how difficult much of the “Apple community” can be when it comes to anything that can’t be adjusted in System Preferences. Googling for problems with external monitors on MacBooks found dozens of threads on official and unofficial Apple forums, all full of people with the same problem. The most common response was to blame the monitor, despite assurances from the stricken users that the monitor worked beautifully in Linux and Windows, even on the same machine under Boot Camp.

“You just haven’t calibrated it!”, “You are just too used to Retina now!”, “You just need to buy a Thunderbolt display!” Apple people also like to solve problems by throwing more money at it. (I realise that owning a Mac makes me an Apple person, too. Hypocritical self-loather?)

My lucky break was reading that the current colour space was “YCbCr” when I was browsing the monitor’s settings menu. I was sure that it was using RGB when hooked up to my PC, so I started searching instead for forcing RGB mode in OS X. It didn’t appear to be available out-of-the-box, but I have had some experience in overriding EDID settings for similar purposes so I searched instead for that.

I found this thread on the forums. Mr Schwarz, thanks very much. Your thread and script was incredibly helpful and informative. It was written to fix problems connecting an external monitor via DisplayPort, but it fixed my HDMI issue just the same. I’ve summarised the required steps below.

My last word is to wonder what Apple is playing at. It seems that this problem has been reported by a lot of people for a long time, and I expect it would require a fairly simple software update. Do they just not care about those using third-party components, or are they actively attempting to force people on to Thunderbolt displays?

How to force RGB in Mac OS X

  1. Download the patch-edid.rb script from the forums thread above and put it in your home directory.
  2. Connect only the external monitor(s) in question (I closed my MacBook lid, for example). The script will make override files for any connected monitor.
  3. Type “ruby patch-edid.rb” in Terminal.
  4. A new folder will be created in your home directory. Move it into the “/System/Library/Displays/Overrides” folder. If Finder tells you that you are overwriting an existing folder, consider backing it up first.
  5. Restart your computer, enjoy your monitor.

To undo the changes, either delete the folder you had copied to the Overrides folder (if it didn’t already exist) or replace it with the folder you had backed up.


I’m not running OS X any more, but if you’re having trouble with any of these steps, please have a look through the comments below (and note that there are multiple pages). Many questions have been answered with helpful tips from others.

Update, 27 Oct 2013: If you’ve applied this fix before, the OS X Mavericks update will overwrite it. I’ve successfully re-applied the fix by following exactly the same steps, and other commenters below have done so, too.

Update, 13 Nov 2013: Andrew comments below that he has modified the script to add some useful new features, and provides a link to his GitHub for those wishing to use it instead.

Update, 28 Nov 2013: If the process appears to work but doesn’t seem to make a difference, consider Tom’s comments below. Depending on your monitor an extra tweak may be required.

Update, 26 May 2014: If you have had trouble with limited resolutions being available after the fix, check out Ibrahim’s comments here.


Modyfikacje w folderze systemowym

[…] przy kombinowaniu w folderze system/library/displays/overrides zgodnie z krokami w tym linku: Force RGB mode in Mac OS X to fix the picture quality of an external monitor | i reckon Miało to na celu wymuszenie trybu RGB mojego monitora, a że nie w tym był problem chcę wrócić […]


Please anyone can help me???

i’m trying to run the script (ruby patch-edid.rb) and i get this

0/universal-darwin13/rbconfig.rb:212: warning: Insecure world writable
dir /usr/local in PATH, mode 040777
patch-edid.rb:11:in `’: undefined method `[]‘ for nil:NilClass

I don’t know what to do, and absolutely no idea what could be the problem

I have a MBP 13 early 2013 retina running 10.9.3


Thanks so much for all involved in this solution. It saved me a $60 restocking fee and return shipping for my new Acer K272HUL display. Not to mention the hassle. Much appreciation all around.


You’re a hero, thanks! Great article. Solved my problem and turned an excellent my excellent Dell U2713H with a good price tag into a perfectly functioning MBPr companion! I used the original patch-edid.rb script and followed your instructions.

Michael Reitsma

well this didn’t work for me.
I applied the script (i used the improved one which generates monitors name in the file) and put it at the correct folder.
I rebooted and it is still fuzzy.
And the colour file itself though is used since my screen now has a title of DELL U3014 – Forced RGB mode (edid override).
It has to do with the 10.9.3 update. I tried to go back to a 10.9.2 version with TimeMachine but the restore failed twice.
So i restored tru a SuperDuper backup to my 10.9.3 version which has this problem unfortunately.

Anybody any ideas here ?


Is it because of the 10.9.3 problem? Have you fixed it now?


Hello everyone,

this is my first post and sorry for my English.

I bought the Dell U2414H and hooked it up with my MacBook Pro Mid 2009. It has the Nvidia GeForce 9400M inside. In near future the display will be connected with a 2012 Mac mini with the Intel HD4000 inside.

My question is: how do I recognize that my setup suffers under the problem that is discussed here? By now, I can give you following details.

On the monitor side:

- I own the revision A00
- I use the original Display Port to Mini Display Port cable
- When I first connected the monitor with my MacBook Pro the Display Port Mode 1.2 was automatically disabled
- The Dell OSD menu tells me that the monitor is running with RGB input format, Mac Gamma and sRGB mode
- For my eyes, everything looks fine

On the MacBook side:

- I runs OS X 10.8.5
- “About this Mac > Monitor” tells me that I’m using “Monitor: Dell U2414H”
- “About this Mac > System > Grafik/Monitor” tells me “TV: Yes”
- “System Preferences > Monitor > Colours > Open Profile” tells me “Colour Room: RGB”

Thank you very very much in advance,


Thanks a lot! The script helped me solving the issue with my Mac mini and HP 2159m monitor. Now works like a charm over the default HDMI output!


The image & screen sizes are matched up with the forced RGB display profile. However, the resolution is still on 1920×1080 @ 60Hz. I’m using the Acer K272HUL as the external/primary monitor, what else need to be modified/added in order to output the 2,560×1,440 resolution, which is the main reason for my purchasing of this 27″ monitor? I’m using an Apple MacBook Pro 13″, Early 2011 with elgato thunderbolt dock output to HDMI. Thank you in advance.


Hmdi has a max output of 1920×1080! Try displayport!


Got it…discovered it with more research after the post. Ordering a mini-display to DP cable to try my luck on the using the Thunderbolt of the dock instead of the HDMI port for video. Thank you.


Worked amazingly well for an Acer K272HUL monitor! Thank you so much!
Fonts are still not as crisp as on Windows 7 but I am using a HDMI cable. I ordered a Mini DP adapter, maybe this will help. At least the Monitor is usable now.


This worked on my Late 2013 rMBP, OSX10.9.3 w/Dell U2410 — many thanks :)

[…] softbunlet wrote: I'm also running a late 2013 15" rMBP and got my U2414H today. Had my doubts about the panel too but everything seems alright so far using miniDP to DP cable included. No wake from sleep or RGB issues. Not bad for the price, but definitely not as vibrant as my Asus PB278Q or the 27" iMac even after my own color calibration. Was a bit reddish/yellowish out of box. Is OSX reading the U2414H as a TV, and using the YCbCr colour space? If you bootcamp, do you notice any difference? Where did you purchase the U2414H? How much? I reckon you've assessed the following links? Dell monitors and apple proprietary hardware/software – Monitors Forum – Peripherals – Dell Community Force RGB mode in Mac OS X to fix the picture quality of an external monitor | i reckon […]

A gargantuan ‘THANK YOU’. Your solution worked fantastically with my DELL U3014 attached to a Mac Pro via HDMI-Thunderbolt.


I just bought a new MacBook Pro Retina 13″ a few weeks ago and for some reason, I don’t have a “Displays” folder within the Library directory. Thoughts?


You have to go to /System/Library. Not /Library or ~/Library.


Damn, I still cannot locate it. I’ve ran some things in Terminal to open up the hidden Library folder, but it’s only the ~/Library folder that shows up and doesn’t contain a Displays folder. I’m not sure what the hell is going on, but PLEASE HELP!!! :)


I believe I left a comment here already, but I just want to say thank you, again. I would have gone insane without this fix. I can confirm it works in Mavericks 10.9.3 as well as Yosemite 10.10 Dev Preview 1 with my HP ZR2440w. Great monitor, by the way. Thanks again!!


Has anyone gotten this fix to work with 10.9.3 and Dell U2414H? Everything in settings looks as it should after applying the fix, however the picture is still fussy after reboot. Just tried with Windows laptop to make sure I wasn’t just picky, but nope – sharpness using Windows is 10x better than OS X.


Todd Cranston

HP Pavilion has the same issue with my mac book pro 2011 and Mavericks. The 23fi monitor shows up as Television, any chance someone with knowledge can help me out with a fix , thanks.


Worked great, thank you!

Etienne Pralong

From Switzerland
Thank You very much this is great !


I tried this with my HP w2207h connected to my late 2013 27″ iMac via hdmi-to-mdp adapter and the test on the HP still isn’t very crisp and seems a little fuzzy. Is there anything else I can try?


*and the text


Has anybody used this script on the new LG 34UM95 Monitor. I use it with a GTX680 graphic card and despite adding the generated “DisplayVendorID-4c2d” folder it keeps showing up as a TV with horrible fonts.

My script looks like this:

Display with forced RGB mode (EDID override)



I forgot to mention, that I’m on 10.9.4. Maybe this matters?


Update: the hack was successful. The correct override folder seems to be “DisplayVendorID-1e6d”. LG 34UM95 now reports as “display with forced RGB mode”. But still fonts look awful. Less color fringing now but detail rendering is not good at all.



I have a late model 2013 Mac Pro with the D300 GPUs and an LG 27EA83 monitor. I am unable to run the monitor in native 2560×1440 resolution. My selections are limited to 1080p at best. I have tried the script here, but the monitor then distorts with lots of ghosting and the resolution remains at 1080p. Using a min displayport to displayport cable. Worked great with late model Mac Mini. I also tried switching display port cables and no change.

I have also tried using Apples $99.00 Displayport adapter with dual link DVi cable. Monitor comes on at boot, and it appears to be in the native 2560×1440 when the apple logo first shows on the gray background, and then the monitor goes dark.

I have also tried StitchresX and it allows me to select 2560×1440, but the fonts are so fuzzy as to be painful in reading.

Much thanks to anyone who might be able to assist with any ideas.


Vimal Kaul

Thanks a lot. This helped on my HP2311X monitor.


Ok, was trying more stuff. The solution: turning the monitors sharpness down from 5 (standard) to 4. Looks a bit soft at first sight, but fonts on Mac PS X 10.9.4 are much better rendered.
Was almost selling my LG 34UM95… now I think I’ll keep it.


Hi Ni,

Did you find a solution for your LG 34UM95? Mine has just arrived, I installed the override correctly (displays the override in System Prefs) but now it wont display at full resolution, it is locked to 1920×1080.

What cables are you using? I’m stuck on Thunderbolt to HDMI until a Thunderbolt cable arrives in the post. Even with the override, the text looks blurry and the colours are wrong, I’m running it off a late 2012 rMBP. Also, I cant access the Sharpness level like you mentioned (it’s greyed out in settings?).


Sorry for replying so late… I drive my LG 34UM95 via Display Port from my GTX6800 video card. Option to change sharpness is active – dialing it down by one just works fine. Hope that with Thunderbolt cable all your problems are solved.


hi guys
just bought a dell 2713hm and i am having the same problems
I’m using an iMac 27inch late 2009 with 10.9.4
i have used the downloaded folder and still the same bad resolution
any ideas with this
im am using the apple mini dv to dvi-d connector with the dell black cable


i contacted apple support about this.
they passed it to the engineers who said – this is how it works. “anti aliasing was on application level” ignoring the fact that it wasn’t looking correct in the finder level.

so there is no solution beyond switching to windows.


also worth noting, nvidia support referenced this article, so the script/patch here seems to be the only solution.


Doe anyone know if this script will work with an ASUS PA279Q 27-Inch Screen LCD Monitor?


yes it works! I have the Asus


Thanks, Ricardo!


Worked great with my AOC Q2963PM!


I probably have the most stupid question but, it 7 pages are too long to see if someone else asked same question. Anyway, I am using late ’13 MBP with retina display and DELL P2414H. I’ve connected it via HDMI from MBP to DVI into monitor.

Question 1 : As I can see here, it is okay to use this cable as hdmi to hdmi too ?

Question 2 : I am still stuck at downloading this script, since I am new to OS X i really hardly understand how to use those scripts. I see there is a zip file for one type of monitor but I am not sure what to do with textual script that is given and it should work for all monitors. Where to copy that text ? If it is text editor, how to name it? Should I place it in folder and zip it and copy to home folder ?

If anyone can be so kind and tell me how to do this step by step ?

Thank you very much!



I probably succeeded to instal this script, but I do not see changes. The picture is not even close to my retina display on MBP. I would appreciate any thoughts. Thanks


Hi There. Need some help

I forced my IMac to RGB and was pretty good. Now I just bought a HP LP2480zx monitor with Color Calibration Solution. Through a AJA T TAP no chance to calibrate but using thunderbolt adaptor I tried to calibrate but the program always crash.
I calibrate this monitor by a laptop and worked fine.
1. Do I need to worry about the color trough AJA? Is well calibrated?
2. Should the monitor keep my last calibration?
3. Is there any chance to calibrate through AJA?
4. Any bad experience with HP Calibration solution?
Thank you all


Hi there!
i am a new MAC user and i am struggling in general with the whole operating system..
now i have bought 2 new BENQ screens however text is blurry as all of you have been facing.
i downloaded the patch however i am not able to create this override file!
in terminal when i write “ruby patch-edid.rb” i get the load error.
therefore i really would appreciate if someone can help me

thanks in advance


Works fine for me on my new mac with benq 27 inch monitor.
follow the steps exactly as mentioned
try saving the script file by right clicking on the link and save as option
copy the saved script to the home by clicking shift command and H
run the script with the lid closed. and the terminal window running on the external monitor.
if it keeps switching off on closing the lid try nosleep app for mac to keep it on,


Many thanks got it working finally!

2 hours trying to figure out that the system folder is here.
install tinkertool app unhide system foders.
go to finder click GO after file,edit,view,go in the task bar
now click COMPUTER or shift ,command , C
find the system folder here!


I followed all the steps mentioned in this post and it just didn’t work for my AOC monitor. After more experimenting, I deleted the Overrides-XXX folder, restarted the machine again and then it magically picked up my monitor and the sharpness was back to normal. I was also fiddling with my monitor settings (hardware), not sure if that helped too. Anyway, might help to someone in similar situation.


I have 2 HP 23xi IPS. And latest MacOs on MacMini.
Run the script. Didn’t work first, then switched cables betweens displays, dvi to hdmi, and from hdmi to dvi and now works!
Thank you, you are genius!


Hey guys

I used MacBook Pro retina display 15′ and my external monitor is LG 29EA93. I have exactly the same problem and when I tried to follow the step I was kinda stuck even on the first step, where do u actually download the script ?

Quin Lausberg

Worked great for me, thanx!

I have a MacBook Air connected with a minidisplay to display port cable from StarTech to a LG 2560×1080 pixel 29EA93 Monitor. After connecting the colors looked awful and fonts looked liked they were made with LEGO bricks.

Now the colors are so bright I have to wear sunglasses but that doesn’t matter I ‘m very happy.

This is a much better advice that the Dutch Apple helpdesk gave me (as always: clean instal).

Very bad that I have to make such changes to the OS myself and Apple doesn’t solved this problem in almost 9 months…

Thanks again for this great article!


hey where did u download the script ?


Worked perfectly, and solved nearly two years of me having to change the input setting on my Dell S2440L from RGB to YPbPr every time the monitor went to sleep. Thank you!

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