Why won't my MacBook detect an external display?

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  • Updated 2 years ago
About 50% of the time, my MacBook doesn't detect an external display. I put it to sleep when leaving the office, possibly use it at home that evening, and the next morning when I return to my desk and connect it to a monitor, it doesn't detect. The "detect displays" command it of no help and a reboot is the only solution I've found.
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Dan Harrelson

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Posted 8 years ago

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Davey

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Always unplug (the display) BEFORE putting the machine to sleep, and plug in AFTER it wakes up. OS X gets confused easily otherwise :)

HTH

- Davey
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Dan Frederick Pitts

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This doesn't "solve the problem." It has the potential to prevent the problem. I wish people would quit putting these smiley faces and "solved it!" stars. Also, my machine DIDN'T go to sleep. It had the AC power supply removed. Intentionally I might add because there's no way I should have had to spend 6 hours trying to fix this tonight.
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Dan Frederick Pitts

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This doesn't "solve the problem." It has the potential to prevent the problem. I wish people would quit putting these smiley faces and "solved it!" stars. Also, my machine DIDN'T go to sleep. It had the AC power supply removed. Intentionally I might add because there's no way I should have had to spend 6 hours trying to fix this tonight.
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meanboy

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Agreed. This doesn't solve the problem.
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tkaryotis

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"6 people say this solves the problem". OK what would these 6 people say if I proposed you have to bang your head with a hammer every time this problem occurs?
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tkaryotis

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"6 people say this solves the problem". OK what would these 6 people say if I proposed you have to bang your head with a hammer every time this problem occurs?
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Cameron Walters

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Agreed. I connect an external display every day when I get to work without any problems. I make sure the display is on, and my laptop is not asleep. If I unplug the monitor and then close the lid on the laptop too soon after (within about 5 seconds) I notice that when I next wake up the machine it tends to be confused.

In summary: laptop awake, monitor on, then plug/unplug, wait a few seconds.
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jb54

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I had the same problem with a brand-new MacBook. I went to the Genius Bar at my local Apple store, and they reset something. They sent me an email with an URL, I'll try to find it.
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Dan Harrelson

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I too have a new (3 month old MacBook) so I'd love to get that URL. In the mean time, I'll try the best practice of unplugging first. Thanks guys!!
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seb

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I can second the "unplug the monitor first" advice. I had this problem too, and since I've started unplugging the mini-DVI connector (and letting the monitor re-adjust to single-display before closing the shell), I haven't had this problem since.
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Lynne Tedesco

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After an hour and being convinced that the monitor was broken, I did this and it worked. The key for me was the unplugging of the mini-DVI connector! Thanks!
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Dan Frederick Pitts

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Well don't take the AC power supply out either or remove the wrong juncture in the chain first either...because those are the two ways I've had it happen.
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Bemmu Sepponen

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I thought my mac or external monitor might be broken since it would not detect it. I disconnected the mini DVI connector. Waited a few seconds, closed the lid. Waited a bit. Opened lid. With monitor still off, connected mini DVI connector. Waited a bit. Turn monitor on. Now it works.
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  • 70 Points
I have a related problem. I unplug my second display, wait, but the macBook doesn't realize the second display is gone. Detect display is no help, and Gather Windows brings up the secondary display control panel as if it were still there. How do I get the macBook to realize the second display is gone short of rebooting?
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  • 70 Points
I have a related problem. I unplug my second display, wait, but the macBook doesn't realize the second display is gone. Detect display is no help, and Gather Windows brings up the secondary display control panel as if it were still there. How do I get the macBook to realize the second display is gone short of rebooting?
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Macbook Pro 10.4 had a problem today which relates to this problem above. The Laptop worked fine projecting a presentation at an offsite location. When I returned to Work and reconnected to a large projector the Macbook Pro would not detect displays. No matter what I did. I rebooted, changed resolutions and nothing but Blue screen. I had to use an older Macbook and Target disk my Macbook Pro to run my presentation. Now I can't seem to detect displays otherwise.
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Dan Frederick Pitts

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HOW EXACTLY DOES THIS SOLVE THE PROBLEM???? Apple has retired the thread on this subject with a similar claim, only they say the problem was solved twice in the thread. I've been working on this for 3 hours now. I read the entire thread 5 times. the last sentence of EVERYONE'S post is "help" this is crap.
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Dan Frederick Pitts

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HOW EXACTLY DOES THIS SOLVE THE PROBLEM???? Apple has retired the thread on this subject with a similar claim, only they say the problem was solved twice in the thread. I've been working on this for 3 hours now. I read the entire thread 5 times. the last sentence of EVERYONE'S post is "help" this is crap.
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  • 60 Points
I don't know if this is related or not!

I have a macbook with OSX.5.3, just over three months old. I have two external monitors in different locations that I connect to with the little Mini-DVI to VGA cable adaptor.

Until recently this has worked fine.

I *think* the problems started after an update but can't be sure. Occasionally I can connect to one or the other monitor and it works, but most of the time I just get the flashing blue screen on both internal and external displays.

Its like my externals are seeing the mac, but the mac isn't seeing the externals.

The times when it does work (I try every day, just about), are so random and infrequent, I can't detect a pattern.

Plugging and unplugging whether the mac is on or off makes no discernible difference. Rebooting with cable in has worked a couple of times, but most of the time doesn't.

Um. Help? Please? Anyone?
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  • 60 Points
I'm stuck with this same problem - I'm seriously getting tired of my Mac - it seems like nothing really works well and there's too many little design geeks trying to jam their bad ideas into one box.

Seriously, I just want to change between two identically resolutioned monitors - they're positioned differently and what works for me - the way "I want to use my Mac" - is to switch the cable between the two.

However, switching an external video cable appears to require a comprehensive shutdown/startup - meaning I have to close about 35 windows, get out my notebook and take notes about what I was doing (isn't that why we invented computers!), change the cable, reboot, then get back to where I was.

Changing a monitor cable should take less than an hour!.

Has anyone figured out how to get an early MacBook Pro (the 2G limited build) running a 10.4 system, to successfully implement VGA without rebooting, etc. Or is this "yet another" Macintosh Mistake?
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  • 60 Points
After upgrading from 10.5.4 to 10.5.5 I went into the same problem too.
My external Display (Apple Cinema) can't be detected by my MacBook.

It's been different versions of X, isn't it about time you guys at Apple fixed this?

Now my Mac Mini is going Vista / Windows Media Center full time.
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kevork

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Hello, same problem here.
After last update, external display is not detected anymore.
Tried any kind of thinks. Reboot, with and without displacy connected, resting display, etc.
Lost external display.
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Ron Smith

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My MacBook is 10.4.11 and it can't detect my brand new Vizio 47" from Costco. The order of plugging and unplugging, starting and shutting down makes no difference. Would a mac mini solve the problem?
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kevork

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Hello,
I had same problem some days ago.
Asked Apple dealer here, they said I had REINSTALL OSX, and get it to version 10.5.4 (I had 10.5.5).
I did not like it at all, so I waited a new system upgrade.
Today, I upgraded OSX to 10.5.6.
Problem has (apparently) disappeared.
I was a torture !.
I Can't not believe that apple site has nothing about this issue, or nothing clear at least.
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kevork

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No way.
I was apparently.
Problem persists, an worst.
Apple, are you there ?.
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  • 60 Points
Same issue here. 10.5.6 update fixed the problem, then a few days ago, out of nowhere my screen started blinking black, and in a few minutes I lost the display. Now no matter what I try I can't seem to get the external display to work in any reliable manner. I have spent days of wasted time on this issue, and everything used to work fine on mac os 10.5.4.

Apple created the problem, but has shown little responsibility in trying to resolve the issue in a timely fashion, and have in no way reassured customers of their competence in dealing with such bugs.

Hope someone finds a way out.
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Piet van Dongen

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Same issue here, just trying to keep the topic alive :)

My display won't return after I opened the lid while working with an external screen and putting it to sleep.
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  • 62 Points
I had this problem and just got used to unplugging my monitor before sleeping the laptop.

Seems to have fixed the issue.
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Piet van Dongen

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How did you get the screen to work again then?
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kevork

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In my case, external display configuration is lost after rebooting, randomly.
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Piet van Dongen

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I have found a solution for my blackout problem, maybe it will work with someone else:

http://getsatisfaction.com/apple/topi...
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enricorpg

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I have the same problem too. Unplugging before sleeping doesn't work, what works is usually rebooting. I hope apple fixes this quickly, I am on 10.6.1 Snow Leopard

EDIT: Works like magic after I return the adapter and getting a new one! =)
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Nikos Stais

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MacBookPro 13'' has the same problem. Detects the external screen. Then laptop goes to sleep. I wake it up. External monitor is not working. I have to wear out display mini port by removing it and plugging it back.

Hello? Anybody in this Company would respond? We may arise this issue loader in many sites? Maybe some professionals could give a solution.

IT'S HAVE BEEN MORE THAN A YEAR WITH THE SAME PROBLEM!!!!
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Nikos Stais

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Buying an original adapter from Apple, solved my problem. Damned cheap aftermarket, non fully functional adapters. worthless
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Mike Gorman

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mine does it with the APPLE adapter:(
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bs

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Same issue here

10.6.2
macbook pro

2nd monitor sporadically works
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macdissapointedme

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A very annoying solution, but it helps, although it generally takes about 15 consecutive attempts:

Not unplugging the DVI connector from the Macbook, but pulling and slowly re-inserting the Cinema Display plug into the tiny connector.

(Macbook OSX 10.4.11)
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solardendro

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My iMac was having a similar problem. I was frustrated because my awesome dual screen background got chopped and my resolution list was lacking the correct resolutions for my monitor.

The solution I found was simple and required no rebooting. All I did was resent my monitor from the monitor's settings menu. After the screen jittered around a bit I would click on the display settings and then detect displays. Voila! All the settings were back to how they were after I perfected my setup.

Apple, in order to keep your costumers buying your over-priced bull ish, you need to fix these tiny bugs that irritate people more than ever! It is bad enough I had to spend 20 bucks to get some adapter because I didnt want to shell out the cash for an apple display.

Pablodius - Mac user since Kindergarten, but maybe not much longer!
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Dan Frederick Pitts

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yea, unfortunately the HP w1858 that I'm using won't allow access to it's menu without a connection. it just goes to sleep. I've spent over 4 hours trying different things and reading about 7 different threads on different websites where the only solutions are preventative; no one has solved the problem except by having the motherboard replaced (supposedly) or having apple (discreetly) give them a URL to reset something. Apple dropped the ball on this one. I am so so so so pissed right now
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solardendro

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I meant to say reset, rather than resent, which was probably a freudian slip!