my macbook pro does not detect external display anymore

I have had this same problem with my MBP. The only solution i have found is a little annoying but works flawless for me every time.

Restart your computer with the cable attached to both the computer, and the TV. Make sure the right input is selected before restart.

Should detect the display right away once you log in.

hope that helps!

Hi Brent,
thanks for the hint, what do you mean by "make sure right input is selected"?
I've restarted pc with HDMI 1 (TV) selected and cable connected several time now but no way to solve the issue.

Hi, after having the same problem, reading all the posts and troubleshooting for two weeks i finally solved my problem. I tried everything i read with no result and was getting into the idea that i would have to wait for apple to fix the problem that everybody believed to be the cause(the firmware update) but i decided to work on the adapter issue. I google reviews for my adapter a "dynex" and read about 3 or 4 post of people saying that the adapter worked fine but it has stop working in a couple of weeks for some and in a week for others. So i decided i give it a try and went to best buy to buy a apple mini dp to hdmi instead of the dynex but the only one they had was again the dynex. So i went ahead and bought it. when i came home and plug my macbook pro that has the 10.6.6 update with the new adapter WALLA!! it just pop in the screen of my sony bravia 55" lcd. so after all this headaches, time and frsustartion it was the adapter that had gone bad. i thought i let everybody know so they dont go through the same Sh$# i went through.

My late-2009 Macbook Pro began this behavior after the 10.6.6 upgrade. I am connecting it via Mini-Displayport to VGA to a NEC brand projector via an Extron brand VGA switcher. Restarting with all the cables connected makes it work all right, but obviously detracts from the Mac's "plug & play" reputation for me :-/

I have just bought the brand new macbook pro 13'' and also a Mini Displayport to HDMI cable (not an adapter) and have EXACTLY the same problem. The MBP could neither connect my TV nor my beamer, and just showed a blue screen for a short moment.

Any news regarding a solution of this issue? Is the problem on Mac OSX' side or on the cable? It's frustrating because I have bought the new MBP mainly to connect it to external monitors and now it doesn't work..

Does your Macbook detect the screen?

In my case ( http://discussions.apple.com/thread.jspa?threadID=2766229&tstart=15) my Macbook fully detects the sceen (I can even move my mouse to the external screen), but the display just won't get a signal.

If you can move your cursor onto the external display and see it there, then obviously the display is getting a video signal. If it weren't, you wouldn't see your cursor on it.

The display is in Extended Desktop mode. Drag a window from your built-in screen onto the external screen, and you will be able to work on both screens at the same time.

If you want the external display to show exactly the same thing as the built-in screen (always at the same resolution setting), toggle the display mode to Mirrored by pressing Command + F1.

I didn't say I can see the cursor. I can't. My screen doesn't get a signal, however the Macbook somehow thinks it does.

So, i am having the same problem, my screen goes blue for 2 seconds and then nothing happens.

I had the same problem with my brand new MBP. Monoprice sent me a new Mini DisplayPort to HDMI cable and it resolved the issue.

p.s. To all the people using Dynex adapters: why? You can get the same adapter for a fraction of the price online. ($25 vs. $7)

Same thing here using MiniDisplay Adapter (VGA) from apple on a Macbook pro mid 2010 , running on 10.6.6 .


This is very frustrating im in the graphic design business and can't work properly from home without 2 screens! Very disappointed!

Hello,

I have the same issues with my 15" mbpro (late 2009):
My external display - connected via dvi - does not work anymore. Some time ago it worked flawlessly. It says: "No video signal". After plugging in the dvi-cable the mac-display flickers, but nothing else happens.

I tried all i know: Switching the dvi adapters, SMC-/Pram-reset, reinstalling the OS (then using time machine), every configuration in display settings, installing various display management-tools (eg. switchresx), switching the external monitor (LG to Philips), switching the dvi-cable, and so on...

However, connecting an external display via vga does work. Using the dvi adapter in windows 7/bootcamp does work, too. (=no hardware-, but software-problem?)

I bought my adapter along with my macbook pro in the apple store.

I'm posting this to show there's one more out there with the same issue which has not been solved until now. Since i'm a graphics-design student i really would appreciate a solution on this matter.

Kind regards, Krakel

Edit: I'm running 10.6.6 Osx

Message was edited by: Krakel

I replaced my 2 year old Macbook Pro with a new MacBook Air yesterday. This was an ONGOING problem with the MacBook Pro and was actually somewhat responsible for my decision to purchase a new Air. I own:

- A MacBook Air 2nd Generation w/ a 13" Display running 10.6.6
- A 2 yr old MacBook Pro running 10.6.6
- A Viewsonic LED 1080p Monitor with DVI and VGA Input Ports.
- an Apple brand Mini DVI > DVI adapter
- a Dynex Mini DVI > HDMI adapter.

The Dynex works beautifully on both machines with my flatscreen TV. It doesn't matter when or how the cables are connected and the machine easily wakes up from the sleep function with no effort. The same adapter / cable won't work with my flatscreen monitor or the Samsung monitor it proceeded.

The Apple brand Mini > DVI adapter works extremely well WHEN it works. There's no rhyme no reason to it's functionality. Sometimes it recognizes the monitor when it's plugged in and effortlessly drifts in and out of sleep mode. I disconnect the machine constantly. It may be coincidental, but it seems to work well for periods of time until something agitates it and it's currently agitated!

I thought I would have better luck with the new machine. It immediately recognized the monitor and effortlessly came out of sleep mode when the shell was closed. It later drifted to sleep and I've been unable to make it work ever since.

The screens on both machines flash blue when the Mini DVI is inserted and then nothing happens. The monitor says "No Signal." I've tried to plug the cable in after the system boots, before the system boots, etc. I replaced the cables. I tried the HDMI adapter that works on my TV and ran a DVI to HDMI cable from the monitor. I power cycled the monitor several times too. No dice. The System Profiler says "No Device Connected." I tried all the different keystroke combinations recommended on this thread and others... no luck. I'm really at a loss.

I posted because I'm hoping someone empowered with all the information (equipment, software version, etc) will be able to help me see something I'm overlooking.

Apple is infamous for creating machines that easily recognize hardware. Even components designed for PC use. I don't know why this is an ongoing issue.

PLEASE HELP!

Same problem here .. I can't connect my Macbook to my TV. I'm using a mini displayport to hdmi adaptor but my TV (sony bravia 32" LED 605) don't recognize any signal... I've tested the adaptor in other TVs and it works... and sometimes it works on the sony bravia...

I'm having the same issue. I'm using a griffin MDP to HDMI & DVI converter with my Dell 2407wfp monitor. I have found that if you change the resolution of your external monitor to 800x600 the monitor wakes up and displays a mirror of your macbook screen for about 1 second. It then displays 'white snow' as though there is no signal (like a tv does). Very strange.