Bootable USB leads to white screen with grey circle with line through it (prohibitory sign)

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Bootable USB leads to white screen with grey circle with line through it (prohibitory sign)

After resetting a 2011 iMac I kept getting the same error in this thread - https://apple.stackexchange.com/questions/258522/mountain-lion-reinstall-failure, so I made a bootable USB to install the OS.

However, whenever I press the command key on startup, I can select the USB which then loads but leads to a white screen with the prohibitory sign in the middle. Like this -

I've made bootable USBs with El Capitain, Sierra and High Sierra using Apple's official guide using the terminal. I've also made the USBs with DiskMaker and they all lead to this screen.

Does anyone know a solution to this? Thanks in advance

iMac Pro

Posted on Dec 12, 2019 8:33 AM

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Answer 1

VikingOSX

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123,716 points

Dec 12, 2019 1:31 PM in response to The Archies

When you state "reset" does that mean that you completely wiped the boot drive, including the 200MB EFI parition and 650 MB Recovery partition? When you say you get to Recovery HD, it that a spinning globe (Internet Recovery)?

Unplug the power supply for 15 seconds and then reconnect (Reset SMC). Try your bootable USB stick again via Option key.

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Answer 2

VikingOSX

Level 10

123,716 points

Dec 12, 2019 11:09 AM in response to The Archies

Try using the Option key instead of the command key. Then select the operating system of your USB stick from those icons presented. What you don't state is what the operating system is on that bootable USB stick. The lastest operating system that can be installed on any 2011 iMacs is High Sierra (10.13.6).

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Answer 3

The Archies Author

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7 points

Dec 13, 2019 2:49 AM in response to The Archies

Right, so I finally got past this prohibitory screen, as we made a bootable USB using diskmaker with an old Macbook which already had the El Capitan installer on it, so we didn't use the downloader from the Apple website, maybe they're different versions to eachother, but the iMac detected this and went to the 'macOS Utilities' page.

After trying to reinstall the OS we did get this message though.

So if anyone from the future has this problem, it seems like the best thing to do is to contact Apple about it.

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Answer 4

The Archies Author

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7 points

Dec 12, 2019 2:42 PM in response to VikingOSX

Sorry, by reset I mean I restarted the Mac with command + R, then erased the main partition called 'Macintosh HD' in the 'Disk Utility' page. If I select 'Recovery HD' when I restart holding the option key, it will take me to the macOS Utilities page.

Here's a pic

But there's nothing I can do here as I get the 'error downloading components' error in the link from my OP if I try to reinstall OS.

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Answer 5

leroydouglas

Level 10

199,752 points

Dec 12, 2019 9:49 AM in response to The Archies

The Archies wrote:

After resetting a 2011 iMac I kept getting the same error in this thread - https://apple.stackexchange.com/questions/258522/mountain-lion-reinstall-failure, so I made a bootable USB to install the OS.

However, whenever I press the command key on startup, I can select the USB which then loads but leads to a white screen with the prohibitory sign in the middle. Like this -

https://discussions.apple.com/content/attachment/5b4e07b9-1acd-481d-8a4c-d2d908d8f128

I've made bootable USBs with El Capitain, Sierra and High Sierra using Apple's official guide using the terminal. I've also made the USBs with DiskMaker and they all lead to this screen.

Does anyone know a solution to this? Thanks in advance

About the screens on your Mac as it starts up - Apple Support

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Answer 6

The Archies Author

Level 1

7 points

Dec 12, 2019 11:54 AM in response to VikingOSX

Ah completely got that wrong there, was meant to type option key but wrote command. I stated that I've tried El Capitain, Sierra and High Sierra, I get to the area where you can select Recovery-HD (which doesn't work as I get the 'can't download components' message), or the USB, which leads me to the prohibitory icon.

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Bootable USB leads to white screen with grey circle with line through it (prohibitory sign)

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