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

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

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

sundy_1 wrote:

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!

This drive has been formatted as FAT (MS-DOS), for Microsoft. You have to erase it, to give it a new partition table. (GUID for OS X Journaled)

Leo

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

What brand external drive?

Your terminal output indicates that it has not been formatted correctly for HFS+

Make sure that you select the GUID partition and not the MBR which is for FAT. Thereafter your disk should be formatted correctly for HFS+

Leo

Thank you so much and I wish I had found your answer yesterday! I spent so much time before finding your solution that worked. After following your instructions and pressing partition from the main listing of my hard drive in disk utilities, I got a message saying I needed to click the external option of my hard drive (which was the listing under the main hard drive) "file" and "enable journaling." After doing that the partition option was no longer greyed out and I was able to successfully partition the drive.

Hi guys, sorry for highjacking the post, but since the problem was already solved, I thought you wouldn't mind.

I had the same problem and used the command posted here on terminal, but still can't partition my external HDD. When I run diskutil list on my terminal, this is what I get now, after using the proposed hfs+ command:

Last login: Sun Mar 27 12:28:21 on ttys000

MacBook-Air:~ TT$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *121.3 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage Macintosh HD 120.5 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

/dev/disk1 (internal, virtual):

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD +120.1 GB disk1

Logical Volume on disk0s2

DE906773-3685-4883-A1E5-A0D123646512

Unencrypted

/dev/disk2 (external, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk2

1: EFI EFI 209.7 MB disk2s1

2: Microsoft Basic Data TT 999.9 GB disk2s2

MacBook-Air:~ TT$

Partition button is still greyed out. Any suggestions?

Thanks

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

This command deletes all of your data on your external hard drive if there's still content on it. So what I did was I used this, then I downloaded Stellar Phoenix Mac Data Recovery - instant download link <http://download.stellarinfo.com/StellarPhoenixMacDataRecovery.dmg.zip>. Run a scan and recover all the data that was on it 🙂🙂 so now you have a hard drive compatible with mac and windows, and still has all your files.

The fact the disk utility is now an abortion in comparison to its past incarnations, have to enter a command line to partition a disk? 3 disks in the machine now I have to enter another command to determine which disk identifier then cross my legs I don't screw everything up? - tell you what why dont I start using CPM again? that was a command line the whole point about macos is one GUI to rule them all, not a dumbed to do to uselessness heap, resorting to command lines is a failure apple I'm continuously disgusted with you nowadays F**ple, sierra is awful. disk utility in 10.4/10.5 was far superior this is ******** retrograde.

Hi guys,

came here for the same problem but turns out the solution was much more easy. You have to select the hard drive (the one with the model number) and not the line with the name that you gave the partition. Then you can partition the disk. Hope it helps.