Cant format or repair usb drive

Question

Matty_1992 Author

Level 1

9 points

Cant format or repair usb drive

Hello,

I am trying to repair my USB drive but it says

Cant open (permission denied)

File system check exit code is 8

Error:Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up filesVerify and Repair volume “WININSTALL”

I am trying to install windows through bootcamp and got as far as creating the partition and booting from USB, but when I booted from the USB I got to the install page and it asked to select a drive but I couldn't see the USB device or any device that allowed me to select it. I thought it may be the format of the drive to changed it from FAT32 to NTFS and then tried to mount the ISO again but it said it couldn't be installed on the USB. So I changed it back to FAT32 and started the process again but it now says error with the USB (when going through bootcamp) so I am trying to repair it hoping it will allow me to mount the ISO and start the process again.

If you could help with the disk repair that would be great. Im ultimately trying to install windows so if you offer any advice on this that would be awesome. Thanks in advance

Posted on Oct 8, 2016 8:17 AM

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Answer 1

Loner T

Level 9

59,471 points

Oct 8, 2016 8:35 AM in response to Matty_1992

Please connect the USB to the Mac, and post the output of the following OS X Terminal command.

diskutil list

You cannot install Windows on an external disk using BC Assistant. The USB device for us as an Installer must be a flash drive, not a USB-connected HDD.

What is the year/model of your Mac?

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Answer 2

Matty_1992 Author

Level 1

9 points

Oct 8, 2016 8:43 AM in response to Loner T

Thanks for the quick response.

is this what you were looking for ?

And its a MacAir mid 2013 V 10.10.4

I have a windows key and ISO file, is it possible to get windows installed on my mac ? Or would I need a usb-connected HDD ?

Thanks

Matt

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Answer 3

Loner T

Level 9

59,471 points

Oct 8, 2016 8:51 AM in response to Matty_1992

Your USB is where the Installer will be created. It will be erased and formatted. You should have an ISO on your Mac's internal disk, parts of whose contents will be copied to the USB along with with appropriate Bootcamp Drivers.

I suggest starting at this link - https://help.apple.com/bootcamp/assistant/6.0/#/bcmp09f5f773 .

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Answer 4

Matty_1992 Author

Level 1

9 points

Oct 8, 2016 9:14 AM in response to Loner T

Thanks for the info. I am following the steps on the link provided but when I get to 'create bootable USB drive for Windows installation' I get the message 'an error has occurred while formatting the disk' I thought I could fix this by repairing the disk but disk utility doesn't allow me to do it. This is where I'm stuck.

thanks again

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Answer 5

Loner T

Level 9

59,471 points

Oct 9, 2016 1:39 AM in response to Matty_1992

Can you try and erase/re-format the USB Flash drive instead of trying to repair it?

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Answer 6

Matty_1992 Author

Level 1

9 points

Oct 9, 2016 1:45 AM in response to Loner T

I have tried that but it just says there is an error and it can't erase the drive. Thats when I thought I would try repair it but it wouldn't allow me to do that either. I have bought another drive online anyway so just waiting for that and hopefully it fixes it. Thanks for all your help and advice

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Answer 7

Loner T

Level 9

59,471 points

Oct 9, 2016 2:04 AM in response to Matty_1992

Can you run the following command but you need to find the value of 'N' first?

diskutil list

Note down the disk number which points to the USB. Run

diskutil eraseDisk diskN

'N' must be the value from the previous command that points to the USB disk. If you use any other disk, you will lose data.

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Answer 8

Matty_1992 Author

Level 1

9 points

Oct 9, 2016 7:12 AM in response to Loner T

HI

thanks for helping me. When I run diskutil list I find it as disk2 but when i enter 'eraseDisk disk2' it says command not found. Should I add in the /dev ? so something like 'eraseDisk /dev/disk2'

thanks again Im sure I can do it through terminal

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Answer 9

Loner T

Level 9

59,471 points

Oct 9, 2016 8:01 AM in response to Matty_1992

Please use

diskutil eraseDisk disk2

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