Hi, all. I'm having an odd external display issue that I can't figure out how to solve. I teach a class using my MBP, and as such have to plug it into the (VGA) projector in the classroom. Up until last week or so this worked perfectly. Now, when I plug the VGA adapter into the Mini DisplayPort, the screen flashes (as though it's detecting an external monitor), but it fails to detect the external monitor. However - and this is the odd part - if I reboot with the cable connected to the Mini DisplayPort, the external monitor is correctly detected at startup.
I tried logging out and connecting it with nobody logged in to the machine, and that didn't work; it's only on a fresh reboot that it will "see" the external display.
The only thing that I can think of that has changed is the 10.6.5 update. It seems fairly clear that my adapter still works fine, as it works correctly at startup... Anybody have any suggestions?
MBP 15" Mid-2010 Hi-Res Core i7,
Mac OS X (10.6.5)
10.6.5 was never the cause of the problem, and 10.6.6 isn't likely to solve it. If you're using a cheap third-party VGA adapter, get a good one, and if your MBP has two GPUs, choose *Higher Performance* in the Energy Saver pane of System Preferences.
MBP 15" Core i7 - mid 2010 model
BenQ G2420HD 24" LCD Monitor DVI / VGA inputs - now discontinued
Acer P1203 Multimedia Projector
Griffin Mini Display Port to HDMI to DVI - purchased from iStore
Apple Mini Display Port to DVI - purchased from iStore
Logitech USB Wireless Keyboard / Mouse
A4 Piece of laminate flooring as mouse pad
Table and chair
Lots of Coffee
When I first started using this screen as the external display on 10.6.3 it worked flawlessly. I updated to 10.6.4 and it still worked 100%.
Ever since the last 2 updates 10.6.5 / 10.6.6 - my external screen does not work. Just shows black screen. As if it is in sleep mode. The screen keeps saying "NO SIGNAL DETECTED"
I formatted the hard drive and reinstalled 10.6.3 - still no video on external screen. Ok so now I am thinking it was the video adapter I purchased a new Apple Mini Display Port to DVI video adapter from the iStore and still not working even though I am now on 10.6.3.
Scratch for 5 minutes.............
I tested both adapters with an Apple LCD screen and only the Apple Mini Display Port to DVI works with the Apple LCD screen.
Next step was to test both adapters with a 3rd display. I tried them both on my Acer Projector and would you believe both the adapters worked fine.
I have tested the BenQ LCD on my other Windows PC - and this works fine on the PC. So the LCD screen does work.
The external screen did come on once on the MBP under 10.6.6 after the reinstall - but now it does not display anything.
I have tried to isolate the issue but I can't as there are different things going on.
So basically both the video adapters work. My LCD screen works.
The only answer is that my LCD screen is not compatible with the MBP - but it used to work for about 4/5 months. So it must me compatible - right?
Why is Apple not responding to this issue as there a number of mac users out there experiencing the exact same issue?
Thanks in advance!
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What I can't figure out is that the external screen used to work on 10.6.3 but after the 10.6.5 / 10.6.6 update and even, now, after a complete reinstall of 10.6.3 the screen no longer works on the MBP. Which does indicate hardware failure.
I tested the LCD screen & Griffin Video Adapter again on my HD Decoder and it works fine. So the screen & adapter is working - for sure.
I even tried connecting my 42" LCD TV to the MBP and it was able to detect the LCD TV under 10.6.6. I pulled the adapter out and tried again to connect to the LCD TV but the MBP could not detect the LCD TV a second time under 10.6.6 (within 5min).
How can it work once and not again on both the external screen and the LCD TV? This is where I am lost.
I have formatted my MBP late last night, again, reinstalled 10.6.3 and I am trying to bring my MBP back to where it used to be, when the external screen worked - will test and keep you guys updated. I will install every software and test the screen, app after app.
And yes I am blaming a software update for all of this as it is the only thing that has changed - everything else is the same. Many users out there are experiencing the same issue and all have stated that it was after the updates that their external display no longer worked. Like Macromedia Freehand - a patch had to be created for it to work in 10.6
Could the updates copy files to the bios/cmos (not sure if Macs have a bios/cmos like PCs)? Like firmware?
What's the best way to revert to factory defaults for everything?
If we are all wrong then come on, show us what the fault is. We all have different instances, but ultimately the same issue - we can't connect our external display to our MBP, especially after 10.6.5/10.6.6.
Hi all, this is a known issue. Hope Apple will fix it soon.... Check the apple's support answer below:
"This is a follow up to Bug ID# xxx. After further investigation it has been determined that this is a known issue, which is currently being investigated by engineering. This issue has been filed in our bug database under the original Bug ID# 8681677. The original bug number being used to track this duplicate issue can be found in the State column, in this format: Duplicate/OrigBug#.
Thank you for submitting this bug report. We truly appreciate your assistance in helping us discover and isolate bugs."
I'm having this problem too. Just spent $50 through Apple's store on a Kanex MiniDP-to-HDMI that does **** all.
Strange part is, it worked okay for a while. Then one day when I plugged the cable into my Mac it just randomly shut off. So I turned it back on, wouldnt boot the OS, restarted, and now I get no output. I didn't even upgrade the OS (it's been the latest one the whole time), just worked fine one day and nothing the next.
Stranger still, during the course of this post I had the cable plugged in and it magically was brought back to life. It seems just moving it around causes it to work/not work. Get yer **** sorted, Apple.
