Unable to boot El Capitan from USB Boot drive

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Level 1

9 points

Unable to boot El Capitan from USB Boot drive

Hi Everyone,

I've created 2 different versions of an El Capitan boot drive using Terminal and on Apples advice Diskmaker X (1 on an 8gb usb stick and another on an internal HD) however neither of which will work for me!

I've tried choosing system preferences but neither boot disk will show up to choose and neither show if I restart holding down the ALT key.

To give you some background I've replaced my video card for an unsuported Nvidia GTX 670 which has no EFI and hence no grey start up screen so could this be the cause of my problem?

I should also mention that I cannot get into recovery mode using cmd-R.

Many thanks in advance...

OS X El Capitan (10.11.3), Nvidia Geforce GTX 670 • BenQ FP241W

Posted on Sep 22, 2016 7:23 AM

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Answer 1

David Mahony Author

Level 1

9 points

Sep 22, 2016 1:50 PM in response to David Mahony

Anyone?

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Answer 2

Eric Root

Level 10

685,341 points

Sep 22, 2016 8:43 PM in response to David Mahony

Can you boot normally with the OS you have installed?

Do a backup, preferable 2 separate ones on 2 drives. Boot to the Recovery Volume (command - R on a restart or hold down the option/alt key during a restart and select Recovery Volume). Run Disk Utility Verify/Repair Disk and Repair Permissions until you get no errors. If you are running 10.11, use First Aid. Then re-install the OS.

OS X Recovery

OS X Recovery (2)

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