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Model A1286. Released February 2011 / 2.0, 2.2, or 2.3 GHz Quad-core Intel Core i7 Processor

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Blue screen with vertical black lines after Apple icon startup


My MacBook Pro seems to boot past the Apple icon and progress bar at startup but then the screen goes blue with black vertical strips.

Booting in single user mode seems to say that it can’t read the hard disk but I have created an El Capitian bootable usb installer which has the same issue and have tried a different drive internally.

I ran a full Apple Diagnostic but this didn’t find any issues.

I have previously attempted to disable the AMD graphics card via Linux which was working fine.

Please can someone suggest the cause of this issue?



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What happens when you go into Target Disk Mode? Does the screen look OK then? Restart the system and hold the T key.

Reference: Mac startup key combinations


I’ve just tried target disk mode it works fine. The screen worked and the drive mounted on the connected computer


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Sadly, your dedicated GPU has failed. Running the system under Target Disk Mode only uses the internal Intel CPU HD Graphics engine. There’s really nothing you can do to fix this all you can do is disable the dedicated AMD Radeon HD 6490M GPU.

Keep in mind the HD Graphics engine is very limited in performance so you’ll need to limit your usage to low graphics types of apps (no gaming). Here’s how to disable it under MacOS dosdude1 - Disable MacBook Pro Dedicated GPU

I would look at finding a 2012 MacBook Pro which has a better GPU sub system.

Given the systems age, I recommend you do a full cleaning of the dust built-up as well as cleaning the old thermal paste off and applying a fresh coat.

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Hi, this helps to me…

Works for macOS Sierra and High Sierra (Improved version)

Taken from StackExchange

Thanks to LangLangC

For temperature and other improvements see

This method leaves brightness control enabled

Reset SMC

Shutdown, unplug everything except power and hold

leftShift + Ctrl + Option + Power

I holded for 5 seconds, but holding just for an instant should work

Reset NVRAM: Power up and hold

Command + Option + p + r

Until you hear the startup chime two times.

Shutdown computer

Power up and boot into Single User Recovery by holding

if you are on high sierra 10.13.6+ you might need to use Command + r instead

Command + r + s

Disable SIP (This takes a bit to complete so wait for it)

csrutil disable

Disable Discrete GPU on boot by running

nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00

Enable verbose boot mode (This will show text everytime you boot up, shutdown or restart your mac)

nvram boot-args="-v"



Boot into Single User-mode by holding

Command + s

It might look as if it hanged, but press enter and you should see the shell (root#)

Mount root partition writeable

/sbin/mount -uw /

Make a kext-backup directory

mkdir -p /System/Library/Extensions-off

Move ONLY ONE offending kext out of the way

mv /System/Library/Extensions/AMDRadeonX3000.kext  /System/Library/Extensions-off/

Inform the system to update its kextcache:

touch /System/Library/Extensions/



It will show a bunch of text in the screen (don't be alarmed, let it finish) and then it will restart again In second restart it will show text in the screen again and then it will show normal login screen Your computer now should work properly (dGPU off and iGPU on, shown as i in gfxCardStatus


If an update that contains changes to the AMD drivers is about to take place it is advisable to move back the AMDRadeonX3000.kext to its default location before the update process. Otherwise the updater writes at least another kext of a different version to its default location or at worst you end up with an undefined state of partially non-matching drivers.

After any system update the folder /System/Library/Extensions has to be checked for the offending kext. Its presence there will lead to e.g. a boot hang on Yosemite and Sierra, an overheating boot-loop in High Sierra.

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