Level 1

41 points

Can't partition (option greyed out) External HDD on Mac OS X El Capitan

Hi guys,

Scoured the net for an existing solution to this problem, but to no avail.

I'm attempting to partition a 500gb external HDD to run bootcamp, but whenever I go into Disk Utility, the option to partition the drive is greyed out.

I've previously erased and formatted to Mac OS X Journaled, so there's nothing on it, but still the partition option isn't available (see screenshot).

Any help is majorly appreciated. Thanks in advance!

MacBook Pro

Posted on Nov 15, 2015 1:48 AM

Top-ranking reply

ajgiii

Level 1

15 points

Posted on Jan 7, 2018 5:12 AM

I solved this issue by using Disk Utility by going up to the Menu bar, selecting "View", and selecting "Show All Devices". Then, the erase and partition buttons became active. I didn't have to get into Terminal at all.

View in context

44 replies

Nov 15, 2015 2:05 AM in response to sundy_1

Erase it with GUID/HFS+. Restart Disk Utility if necessary. That should give you the Partition button back.

Nov 15, 2015 2:39 AM in response to sundy_1

Open Terminal and type "diskutil list". Post the output here.

greg sahli

Level 7

25,508 points

Nov 15, 2015 6:12 AM in response to sundy_1

Still shows no indication that it's been formatted HFS+.

What brand external drive?

sundy_1 Author

Level 1

41 points

Nov 15, 2015 6:26 AM in response to greg sahli

Greg wrote:

Still shows no indication that it's been formatted HFS+.

What brand external drive?

It's Seagate, Greg.

Best,

Tom

Leopardus

Level 4

1,303 points

Sep 4, 2016 11:17 AM in response to Don Knaught

Don,

Kindly start your own thread concerning your exact problem. It will receive it's due consideration from the community on it's own merits.

Leo

Dec 31, 2016 4:18 PM in response to Alberto Ravasio

Thanks a million Alberto.U are the man!!😉

LSN1986

Level 1

4 points

Mar 9, 2017 5:01 PM in response to Alberto Ravasio

You rock, Alberto! This was a huge help, thank you!

Mar 14, 2017 11:16 PM in response to traceyinhenderson

Thank you, this worked for me. 🙂

Jun 22, 2017 8:33 AM in response to Alberto Ravasio

dude this erased my hard drive instead of partitioning it.

Jun 22, 2017 10:40 PM in response to Ratchet99

As a matter of fact partitioning a disk means destroy its content.

Also the command is quite clear

diskutil erasedisk hfs+ External GPT /dev/disk2

Jun 23, 2017 6:14 AM in response to Ratchet99

The label Partition in Disk Utility is misleading. The more appropriate word should be Resize.

andruhvy

Level 1

9 points

Jul 20, 2017 12:17 AM in response to Eric Root

Many thanks; I have done a feedback submission.

Jul 23, 2017 4:31 PM in response to maossand

Good stuff ,problem solved ,thanks

Jul 28, 2017 12:19 PM in response to Alberto Ravasio

From looking over than command it looks like this will "erase disk." Is that correct? I'm looking to keep all of the data without having to format the disk.

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Can't partition (option greyed out) External HDD on Mac OS X El Capitan