Cant 'Partition' new USB drive to make it bootable installer (to create external drive as startup disk)

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Level 1

19 points

Cant 'Partition' new USB drive to make it bootable installer (to create external drive as startup disk)

Cant 'Partition' it. The Partition button is disabled surprisingly. Only 'mount' and 'partition' buttons are disabled. but 'First Aid' & 'Erase' is Enabled.
Just unboxed new 16GB USB3 drive to make it boot ready. ( Upgraded OS from Yosemite to El Capitan 10.11.2 and yesterday I could use 'Partition' command for Internal MacHD & created a test 50GB encrypted partition drive)

I want to do a fresh clean install, so I wanted create this ext backup start up disk before erasing the internal macHD disk.

MacBook Pro with Retina display, OS X El Capitan (10.11.2), New Mac; Setting up req stuffs.

Posted on Dec 12, 2015 2:25 PM

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Answer 1

MrHoffman

Level 10

150,211 points

Dec 12, 2015 7:00 PM in response to applpal

Erase the disk via Disk Utility, and then partition the device — whatever present format was used at the factory is probably lacking the GPT structures that would be expected. This does erase the entire contents of the disk, so make sure there's nothing on the disk you need.

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Answer 2

applpal Author

Level 1

19 points

Dec 12, 2015 7:17 PM in response to MrHoffman

Thank you. U r right. I did so with GUID option. I thought Erasing might have helped to make the USB boot ready. But I have not done the partitioning after erasing. That's why may be when I was trying to execute the command for boot-install from terminal, it said 'command not found'.

Let me try partitioning it first.

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Answer 3

applpal Author

Level 1

19 points

Jun 24, 2016 1:51 PM in response to MrHoffman

Quick ( happy) update! I did the partition. But even after that command was not executing in terminal.

Then tried re-partition again with 2 volumes with one as more than 8gb. and then command line. But failed the installer command.

When I removed admin$ from the whole line then it worked 🙂. Now it is 'copying installer files to disk.....' Hopefully it will be successful within few mins. Thanks lot for partitioning idea after erase. and caution too. ✅

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