Model A1297 Unibody: Early 2009, Mid 2009, Mid 2010 & Late 2011

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Mac display screen works only when external monitor is connected

Hello all,

I have been trying everything over the last 3 weeks trying to fix this computer, and I am now to the last option which is contact you all for an answer.

I have this 2011 Macbook pro 17" on OS X EL captain which gives me a flashing dark Bleu screen on normal mode. the start up is successful, but it just now showing anything on the screen beside flashing every 3 seconds.

1) I connect an external monitor to the DisplayPort the computer On and works just great, with that said, i have both the mac monitor and the external monitor(my TV) work fine. I unplug the external monitor to see if the mac monitor will stay fine NOP it did not. The mac screen went dark bleu and start flashing again.

2) I tried safe mode and the mac monitor works fine with out the external monitor attached to the displayPort.

If i want to use the computer in normal MODE an external monitor as to attached to the displayPort. Even if i turn the external monitor of the computer monitor still work fine, but the moment I unplug the external monitor the dark blue screen comes on, and the computer start to flash and i can't see anything at all.


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I tried another drive, reinstalled the OS X, tried recovery mode, etc. I still get the same problem.


Hi Zanz Zan ! Did you find any solution eventually? Because I have the same problem ... almost


Did you read the post? There is a chosen solution, which means it worked


Yes . And i have the same problem


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If your display works fine in Safe Mode which is what you seem to have said, it's a software issue.

You may have picked up a virus. I would boot it in Target Mode with another Mac that has a good (paid of) anti-virus such as Symantec.

You can also try starting in recovery mode and running disk Utilities. Here's how:

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Sounds like the display issue may be caused by the graphics processor, all 15 & 17" 2011 macbook pros have been recalled for that reason. It's possible you can have it fixed free of charge if it's a 2011 model. See here

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ZANZ ZAN will be eternally grateful.
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