Using Disk Utility in El Capitan, I cannot partition or erase external USB drive.

[benhurt]

Hey all,

I've done the install on multiple CustoMacs around my office just to learn more about the process. Everything has worked fine in the past.

I'm trying to create the USB drive on my MacBook Pro with El Capitan. The Disk Utility in El Capitan doesn't play well at all. I can't write to or edit any USB drives that are ISO 9660 formatted, and it won't let me repartition, erase or format them either.

What's the deal? How do I format the USB drive from the terminal? Those steps don't work in El Capitan either.

Thanks for any response!

 

[BananaT0m]

You can try to erase your USB directly from the terminal. It works everytime

EDIT: in your terminal enter "diskutil list" and enter. Locate your USB with his disk number and enter "diskutil eraseDisk JHFS+ USB /dev/(name of your disk)" and enter.

 

[benhurt]

Sorry, that does not work either. I have several disks I've used for various Linux installs and none of them can be erased or partitioned with El Capitan Disk Utility or the diskutil command line tool.

I had to put the USB drive in my other machine that still runs Yosemite to partition/erase them and make them JHFS+ to use as an install disk.

Any suggestions why El Capitan can't do it?

 

[alcanfane]

Sorry, that does not work either. I have several disks I've used for various Linux installs and none of them can be erased or partitioned with El Capitan Disk Utility or the diskutil command line tool.

I had to put the USB drive in my other machine that still runs Yosemite to partition/erase them and make them JHFS+ to use as an install disk.

Any suggestions why El Capitan can't do it?

I had this problem before but I solved by partiontion it using windows 7 and re-partition again on the El Capitan. It works well for me.

 

[benhurt]

Yes that's an option, but we used to be able to format USB drives in disk utility. It's not a CustoMac issue, this is on my MacBook Pro Retina. I used that feature all the time with my business.

I guess I need to find a 3rd party solution of some kind.

 

[Russmcb]

It looks like we lost the ability to partition USB drives in the "new and improved" Apple Disk Utility app. Sigh...