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sundy_1 Author

Level 1

40 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

8 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

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.

Oct 13, 2017 11:53 PM in response to Leopardus

Sadly this wont work on my new 4TB WD drive

I tried the work around using terminal as well.diskutil erasedisk hfs+ External GPT /dev/disk2

Still nothing works?

Barry

Oct 14, 2017 12:11 AM in response to barrylsack

This thread is marked as solved. Please start your own explaining exactly what your problem is.

Oct 14, 2017 12:26 AM in response to barrylsack

OK Ihad to reformat back to OS journaled to solve this then it allowed the partitioning.

It will not allow it to partitioned in EXFAT

Barry

rancoen

Level 1

8 points

Jan 8, 2018 3:07 AM in response to Alberto Ravasio

Thank you! at first try using the command you provided I got an error so I was afraid it wasnt gonna work, but luckily when I tried again a few minutes later it did work!

Jan 18, 2018 2:13 PM in response to maossand

I'm sorry to bother you with this silly simple question but where is the option with the model number? I'm having a tough time locating it. Thanks in advance!

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