How to stop flickering on an Apple LED Cinema Display


The Apple  24 inch LED Cinema display  and the Apple thunderbolt display have been a  source of frustration for many people.   They flickers, go black, the screens gets garbage on them, the fans turn on and off.   After reading lots of forums and trying various things I have practically completely eliminated all the flickering on my  24 inch LED Cinema display,  here is how.

My story

I am running a Mac Mini  and one of these Apple LED cinema displays:

LED display

It’s  had a problem with flickering ever since I first got it back in 2009.  It started off that once a day or so it just went black for five seconds.   At other times  the  screen is completely filled with gobbledygook  until I sleep the display and restart it.   At other times the screen just flickers black for a fraction of a second,  but all the fans  in the screen power down and then power up again.  Apple have released various ‘fixes’  to the problem over the years which have never fully resolved  the problem. Phone calls to Apple support were of no use after the first year because they just claimed it was a hardware problem and ‘out of warranty.’  The flickering got extremely bad recently with ‘El Capitan’   and the flickering also got worse when I connected a Pegasus Thunderbolt hard drive.

Other People’s Stories

It’s not just the Apple LED Cinema display that has been affected. Even Apple’s latest ‘stunning’ Thunderbolt Displays have problems too.  The Apple help forums are riddled with complaints…

Thunderbolt Display Flickering Epidemic

27” LED Cinema Display flickers

24 inch LED cinema Display momentarily goes black

Flickering Thunderbolt Display

New 27″ Thunderbolt Display Flickers


Apple have released various ‘fixes’ over the years which don’t seem to work:

LED Cinema Display Firmware Update 1.0 (2010)

Thunderbolt Display Firmware Update v1.1 (2015)

Thunderbolt Display Firmware Update 1.2 (2015)

What to do?

Firstly, don’t buy any kind of Apple thunderbolt display!

But if you already have one, here are a few things that might help.

  • Run  the display directly from your Mac Mini,  do not daisy chain it with a hard drive such as the Pegasus Promise.  Daisy chaining definitely caused more problems.
  •  Do not plug any USB devices into the USB ports on the LED display.
  • Run your screen on full brightness,  some people have reported that the problem is worse when the brightness is lower.
  • Wrap your  thunderbolt cable in aluminium foil to shield it. (I kid you not -this worked for me – see the pictures below).
  • Try unplugging and plugging the thunderbolt connector or Apple display port connector,  sometimes the problem can be worse if the connect is not in tightly.
  • Reset your SMC (System Management Controller). ( Turn off your computer,  un-plug the power cord,   wait 15 seconds,  plug it back in,  wait five seconds,  turn it on.)
  • Reset the NVRAM. (Shutdown your mac, restart, hold down Apple-Option-P-R while it starts. release after the second chime)
  • I have a 2009  LED Cinema Display, but if you have a newer thunderbolt display, try replacing the all in one cable with a  thunderbolt cable.  A lot of people have found out the problem was with the cable.  You’re probably better off trying to borrow a thunderbolt cable  or seeing if your local Apple store will lend you one because they are in excess of $50 each.
  • Try using the shorter 0.5m  thunderbolt cable. ( You can’t do this on the LED Cinema display because the cable is built in to the display).
  • If  you are having really bad problems, make a corner of your screen a hot corner to put your display to sleep.  sometimes my computer is blinking so badly the screen goes crazy and I can’t see anything,  I can’t even see the menus to ‘ restart’  the computer.  But if I move my mouse to the ‘hot corner’  to sleep the display, and then wake the display up again sometimes the problem goes away.

Crazy as it sounds,  wrapping my thunderbolt cable in aluminium foil was the biggest help of anything.  I looped up the excess thunderbolt cable into a circle and put aluminium foil around it to shield it.



Here I have activated the bottom left hot corner so that it puts the display to sleep. When things get really bad I can put the display to sleep with my mouse without having to see what’s happening on the screen. Then I can wake it up again with my spacebar and more often than not the problem has fixed itself temporarily.

Hot corner

All the best and let me know if anything works!











28 responses to “How to stop flickering on an Apple LED Cinema Display”

  1. rikrayrik

    I still have the same problem with my 2009. It isn’t clear, do you have a thunderbolt cabled monitor? But that can’t be for 2009, right? I have the mini display port. I am wondering what of your fixes would apply and that I should try.

    1. I have 2009. Mini display port. It connects to the thunderbolt external pegasus drive that I have. Try everything till it stops flickering.

  2. Hans Sieburg

    Thank you for putting this together. The only thing that helped me was to put the USB connector of the 3-way cable into the Mac Pro, as well. I found this hint in some other forum. Also, I noticed that before using this fix, I had no problems under Snow Leopard, then problems when I upgraded to Yosemite, then no problems when I upgraded to the first version of El Capitan, and then problems again under El Capitan vs 10.11.4. Thus, the operating system version may play a role, also.
    Sad as the whole on-off, black-out and flicker issue, I was grateful to see the picture that you included. It made me laugh (no disrespect meant), because it reminded me of similar fixes in 1974 to an IBM card reader. Apple should be doing something about the screen problem, because your picture is a beautiful negative marketing example to me. But, alas, from what I read on other forums, they do not seem to be interested.
    Again, thank you.

  3. Glen

    Are you still using the display? Curious how your fixes have held up or if you have had any success with newer MacOSs.

    1. The display completely died 6 months ago. :-(
      Up until then it was working fine.

  4. Cam

    Thanks so much for this. I have a 3rd party Thunderbolt display that has been working fine for years connected to my Mac Pro. I recently connected it to an iMac and this ‘known good’ display has since been flickering like crazy and driving me nuts. I grabbed some foil tape and wrapped the first 3 inches of the connector where it connects to the iMac (obviously not the metal part of the connector!) Since reconnecting ..not one single flicker. Much appreciate this post!!!

    1. Glad to hear it worked!

  5. Piipperi

    Sadly tried all of these solutions on my 24″ LED Cinema Display connected to my MBP. Still flickering and sometimes turning off. Time for a new backlight maybe?

  6. shannon

    My thunderbolt display was just now flickering like it ofter did. I pulled off the connector from the back of the computer and put some fluid film in had worked perfect since. I think there is a issue with the pins getting good contact in the port…

    1. Matthew

      Can you elaborate a little? I have 24” ACD LED I acquired that flickers or just won’t power on unless the power cord is inserted “just right”.

  7. nsouch

    I just purchased a (used) 24 inch Thunderbolt Display that seemed to work well on the macbook pro during the demo.
    Back at home it started flickering on both of my 21 inch imacs. I tried the aluminium foil trick unsuccessfully.
    Though it seems not recommended, what solved the problem is *daisy chaining a Lacie eSata hub* in-between the imac and the display.

    Note the thunderbolt cable is 2 meters which is quite long but the connector is much more strongly inserted in the imac than the display’s one.

    Hope this helps your investigations !

  8. Andrew

    Unplugging any extraneous cables and not using the ports on the display (i.e. Thunderbolt, USB) has worked for me. For a company who charges a steep premium for their products and who now has more than $1,000,000,000,000.00 in cash really should think about taking care of the loyal customers who got them there. Maybe each display comes with a free roll of Reynold’s Wrap?

    Wow, I’ve never actually written out One Trillion before.

    1. Well said Andrew!

    2. Matt

      Sadly, that hasn’t been the case in a loooong time. I used to work for Apple back in the 80’s and 90’s and it was a very different vibe. It’s all about selling new machines to new customers now. Their support is exceedingly unforgiving and cold compared to where it used to be.

  9. Roger

    I HAVE HAD THE FLICKERING ISSUE WITH 23″ CINEMA DISPLAY. I tried all 3 methods, no success. I said F@!#$@ it, its broken anyways………<<<<<(KIDS DO NOT TRY THIS AT HOME WITHOUT AN ELECTRICIAN>>>>>>>YOU COULD DIE!)
    I cracked open the power supply, remove the board that connects the display, stripped the display cable and soldered the 4 cables. Issue Resolved! The power supply board has 2 cables attached, and so did the display connector once I cut off the head and stripped the cable. I chose the darker color (blue I think) with the black (-) and red with tan (+). No aluminum foil needed. Again, do not attempt this if you are not a certified electrician. YOU CAN DIE IF YOU DON”T KNOW WHAT YOU ARE DOING!

  10. Tahina

    Hi Roger !
    Can you explain in details your procedure ?
    I’m desperate and really interested

  11. Scott Anderson

    I had a lot of trouble getting my 23 inch Apple Cinema Display to connect to my Macbook 2017. I needed an active DVI cable. But when I finally got it connecting, it began to flicker. It quit when Apple support shared my screen. When it went to sleep, it woke up and began to flicker. I launched zoom, when I turned off the display for about half an hour, the flicker was gone. When it went to sleep, woke up, the flicker was back. Now I don’t let my computer sleep, and it works fine. Waiting to see if Apple has a fix. I would like my computer to sleep, but I can’t work on the smaller screen of the macbook and I can’t work with the flicker.

  12. Liam Meighan

    The aluminium foil trick worked a treat on my Thunderbolt 27″ Display connected to the 2012 Mac Mini.

    Only in recent years has it started to flicker and I was relentlessly swapping the cable between mac and 2x OCW Thunderbay IV. I’m maxed out on Catalina so it’s been flickering that long intermittently.

    Now the big Q – will it work on a current Intel or M1 mini?

  13. Omi Nima

    I have a 2009 LED Cinema Display that starting doing this with my 2018 MBP. I initially called Apple support and they mentioned it is obsolete with no support options. I have then replaced the logic board (a used, working one from eBay) to no avail. I finally tried the aluminum foil, and it is still not working. I really hope there is some solution as I would not like to discard this almost-$1000 display (we’re the original owner). Would greatly appreciate any more suggestions. Thanks very much.

  14. Steve

    I have a 2004 30″ Cinema Display. After 18 years of trouble-free operation, it flashed on/black about a day after I connected it to a Dell via the HDMI. I attributed the issue to the Dell, single-link, inadequate GPU, travel bumps, whatever. So I brought it home and connected it to my 2014 MacBook Pro, but found the same thing: fine for a day, then this flashing.

    Unplugging and replugging at the brick (the 30 has its own big white brick) stopped the flashing. It seems fine so far.

    1. Cat W

      In my case, it starts out just a few times a year, then gets progressively worse.

      1. Mine eventually completely died.

  15. Andy

    I have a 2013 27″ Thunderbolt display connected to a MacBook Pro. The screen flickered on and off constantly. Had the power/thunderbolt cable replaced. That fixed it for a bout 2 years then it came back. Have now bought a new thunderbolt connector and plug into the spare thunderbolt input on the back of the display. No flicker. Happy days.

    1. Amir

      Hi Andy, I have a 2013 27 Thunderbolt Display connected to 2018 macbook pro, and get constant flickering, it only happens when the macbook has been connected to the display for a longer period of time, disconnecting and reconnecting it doesn’t help. if I disconnect it for a few days and connect back it wont flicker, was your issue similar? can you tel me which cable you got to fix the issue?

  16. Elvin

    Been using my 30″ Apple Cinema Display with an HP laptop and my MacBook Pro. At first the flashing was only my MacBook Pro then recently on the HP. I thought it just needed to warm up. After reading this post (thanks Wayne!) I went ahead and made sure none of my cables overlapped each other (laptop power, ACD power, ACD all-in-one cable including the loose firewire and USB ends, and video adapter cable to either Mac or HP).

  17. Elvin

    My Mac seems to be more stubborn and has a different source to the flickering that isn’t as easily resolved. It appears that the power button is on the fritz and is the reason for the flicker. (it acts as if someone is repeated trying to turn the display on/off).

  18. Elvin

    Though it is a 30″ Apple Cinema Display that flashes (my 24″ ACD doesn’t have this problem as stubbornly). I’ve found now that not plugging in the displays USB cord eliminates the interference that caused the flashing. It’s not needed unless you want to use the screen as a hub, but even plugged in, I haven’t found the USB screen ports to be working.

    So problem seems solved for both Windows and Mac usage and not dependent on the power button.

  19. Cat W

    The aluminum minimizes the flickering somewhat, but not totally.

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