Currently Being ModeratedApr 21, 2013 3:39 AM (in response to donpd)
Nevermind, i found a fix for it
Thanks to neilb41 for the fix.Re: my macbook pro does not detect external display anymore
I hesitate to add to such a long thread but after weeks of frustration (and suffered ridicule when I could not use my Mac to support a presentation!!) I finally stumbled on a simple solution.
I had previously repaired permissions without apparrent success but I would recommend doing this as poart of good housekeeping anyway. Then I reset the PRAM. PRAM holds a number of system settings while your computer is switched off... including the display settings. To do this (copied from http://support.apple.com/kb/ht1379)
- Shut down your Mac.
- Locate the following keys on the keyboard: Command (⌘), Option, P, and R. You will need to hold these keys down simultaneously in step 4.
- Turn on the computer.
- Press and hold the Command-Option-P-R keys before the gray screen appears.
- Hold the keys down until the computer restarts and you hear the startup sound for the second time.
- Release the keys.
Worked for me first time. I wonder why Apple could not have suggested that as a reply to the thread!!
Currently Being ModeratedOct 3, 2013 7:22 AM (in response to donpd)
I have tried this process twice and it still will not detect my external monitor. I am lost for ideas and have tried every thread available. Sending mine in to the Apple store today to fix this problem I use my external monitor for coding and its hard on the eye sight when using this one on the Macbook Pro.
Currently Being ModeratedOct 21, 2013 5:52 AM (in response to braytonscott)
have you considered using another thunderbolt hdmi cable?
Currently Being ModeratedMar 6, 2014 7:10 AM (in response to donpd)
For what it's worth: I had similar problems: I have a Mac Pro (2,1) with a 5770 graphics card. The card supports three displays (one DVI, two DP ports). I have two 30" cinema HD displays connected to it and one AOC 24" FullHD monitor via DP.
Quite frequently, the AOC would not be recognised when waking from sleep and I had to force the computer to detect it (unplugging cables, etc.). Given that the Mac Pro is about 7 or 8 years old, I changed the 3V Lithium backup battery (Panasonic CR 2032). That changed it completely and I haven't had any more problems.
Give that a try.