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computer recognizes projector, but projector doesn't recognize computer

Hi!

I am trying to connect a video projector to my new MacBook Pro (specs see below). I have tried with two different projectors and failed. Both projectors used a VGA cable, which I connected with Apple's DVI-to-VGA adapter (bought with my previous 2006 MacBook Pro), which I then connected with a third party (LogiLink) Mini DP-to-DVI-I adapter, which I connected with the MacBook Pro.

The projectors DO show up in the "Monitors"-menu, so they are recognized by my computer. The MacBook Pro also immediately went into sync mode and adjusted its screen resolution to that of the projector. However, both monitors only displayed their blue screen "searching for input" message, so both didn't recognize any signal coming from the computer. When connected to a Wintel laptop, both recognized it immediately, and displayed its mirrored image. Connecting back to my MacBook Pro, again only the blue "searching for signal" screen. Even putting the MacBook Pro to sleep and waking it up didn't resolve the problem.

I am at loss to what is the reason. From my 2006 first generation MacBook Pro I am used to plug&play when it comes to projectors. No restart, no keypress needed on the computer. Has that changed somehow with the newest generation? (I am also missing the F7 monitor switch key, but that's a different matter, isn't it?)

I have activated the firewall and the stealth mode. Can this play a role? I wouldn't think so, however.

Help very much appreciated.

McBook Pro Core i5, 15'', 2.4 GHz, 4GB, Mac OS X (10.6.5), NVIDIA GeForce GT 330M

Posted on Dec 6, 2010 9:53 AM

Best reply

TheShortStory

Level 1

8 points

Posted on Mar 19, 2011 5:47 AM

I have a similar problem as well. my 13" 2011 mb pro recognizes my external display (connected via mini-display to hdmi adapter) but the display doesn't recognize the input signal. On my windows partition, though, it works perfectly....!

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23 replies

M Goebel

Level 1

0 points

Apr 22, 2012 8:45 AM in response to Martin Schmitz-Bethge

I now have the same issue and none of the suggestions above worked in any way. With the same miniport-VGA adaptor, once connected to the projector, the computer obviously recognizes the external projector because it switches to a different resolution - also with the "detect displays" I do get the projector. But the projector continues to say there is no signal. The problem is compounded because, once connected, the computer gets all heated up and becomes so slow that it is almost impossible to adjust any settings or even get to the systems preferences (e.g. to change the resolution of the projector, as suggested above).

Jun 17, 2012 10:37 PM in response to Martin Schmitz-Bethge

I am having the same experience as M Goebel, down to the sluggishness of response by the computer. Does *anyone* know what causes this, and what to do about it? I'm a history teacher, and I'm desperate to turn my notes into presentations -- but I can't get the projector to "read" the computer.

Contrarily, is there a projector make/model that doesn't have these issues with MacBooks? I'm frustrated enough to consider buying my own projector, if it'll work with my computer.

While I'm working on a 2-month-old MacBook using OS X.7.4, I had the self-same problem with my previous MacBook, which was a year old & using OS X.6.___.... but did NOT have the problem with my 3-year-old MacBook that was probably using OS X.5 (or an early version of OS X.6).

Jul 30, 2012 12:51 PM in response to _ratfink

Last week I had no problem projecting a webcast from my Macbook Pro 10.6.8 via a school projector. This week, after downloading Mountain Lion, it didn't work-- no signal. I've learned what to check for from these threads, but does anyone know if OS 10.8 would make this connection more complicated? I'm using mini display port to VGA.

Aug 4, 2012 1:36 PM in response to Martin Schmitz-Bethge

The same problem with my newest mid-2012 MacBook Pro 13 inch, 2.9 GHz Intel Core i7 running Lion 10.7.4.

It has suddently stopped recognizing projectors after 2 weeks since I've bought it. After a day of troubleshooting, I have verified that the VGA video cable and Apple's MiniDisplay Port to VGA adapter were working. And then suddenly everything seemed to be back to normal - and I could connect it again to a projector. But the following day connected MacBook Pro to projector and all I could get was again the black screen with flickering thin vertical whitish lines. I always use extended desktop with the projector.

More troubleshooting... At the end WHAT SOLVED my problem:

(1) Started my MacBook Pro into safe boot:

http://support.apple.com/kb/HT1564

(2) You may want to try doing this with projector connected or disconnected. Got extended desktop through the projector.

(3) Disconnected MBP from the projector. Restarted MBP as usual (NOT safe boot). So far, after a week of use (and no restarts) MBP was connecting properly to 4 projectors.

Aug 25, 2012 6:23 AM in response to Wunderkind

After troubleshooting the above issue, I can confirm that for solution to work consistently one needs FIRST to connect MacBook Pro to a projector and only THEN reboot it into a safe boot.

Sep 13, 2012 3:39 AM in response to Wunderkind

thank you so much! u solve my problem perfectly! \(^_^)/

Lemoda

Level 1

0 points

Sep 13, 2012 4:59 AM in response to Wunderkind

Thanks a lot ! you have also solved my problem. Take care 🙂

Jan 22, 2013 5:41 PM in response to Martin Schmitz-Bethge

Deleting the window pref files solved the problem, but only after two restarts. Go figure.

computer recognizes projector, but projector doesn't recognize computer