unable to partition external hard drive in disk utility

and I have the same problem. I have tried this on my original Toshiba 500gb and have now bought a new Toshiba 2TB.

I have erased all, using the 'GUID Partition Map' scheme and Mac OS Extended (Journaled) format.

When I go into the Partition tab, the +/- is faded out

Whilst I'm pleased this isn't only me, surely there must be a glitch if so many of us are getting it wrong?

NB: I'm using macOS Sierra, version 10.12.6

thx

I am having a similar problem. I have a new MacBook Pro (Sierra) and want to use an external drive for Photos. I have a new Toshiba 500GB external drive that was NTFS out of the box. I want to format it to Mac OS Extended (Journaled), and partition it into two 250 GB partitions, one for Photos library, the other for Time Machine. Sounds simple, but disc utility will only let me erase, format, and rename the original partition. The partition button stays grayed out. I've tried everything, no luck. Am I missing something, or is there a work around? Thanks!

I have the same problem in Sierra - I think your "complaint" comment is misdirected.

Brand new Seagate external drive, partition is grayed out. I have selected the drive - there IS no "+" button.

Now what?

As Kappy showed above, select the main drive you want to partition, not the indented disk below it in the sidebar.. The partition button should now be black. Click on it and partition the entire drive the way you want it using the ➕ to create more partitions or ➖ to delete a partition and click apply. The + and - buttons are at the bottom.

Except when there is NO "+" there. Did you read the posts above or just reply with what you believe to be right? I know how to select a drive and not the partitions below - and there are none anyway. And NO "+" button!

Apparently not -- I am having the exact same issue -- I have purchased a WD 4T External drive and want to partition 1T for my Time Machine. When I highlight the appropriate name, I get all options except for Partition and Mount... these are greyed out. I have checked online and cannot figure out why the partition is greyed out.

Can ANYONE help. This is beginning to really frustrate me.

Thanks,

Simon

Same problem with a Seagate Expansion 1TB Portable Drive, want to partition into 2 one for a full SuperDuper backup and one for Time Machine. The + button is ghosted out, cannot add another partition.

Running EL Capitan

Sadly I cannot partition my 4TB WD drive.

I have erased it all but the "+" is greyed out and it will not allow me to alter the 4TB main partition section either?

Any assistance gratefully received

I check the instructions and followed them completely - but nothing seems to help?
Regards

Barry

I had same problem, but then fixed it (partly from clues given by "fuzzymo" above)

I have an old Windows NFTS formatted external drive, I had then used the iMac Disk Utility to format ("erase" in Mac terminology) as "macOS Extended(Journaled)" which worked BUT no ability to Partition (as many people here have experienced. My fix for this is that I discovered that I had not changed "Scheme" (when setting "erase" options) from "Master Boot Record" to "GUID Partition Map". Once you do that which is a new "erase" you get full access to Partition options.

Hope that helps

I have just spent an hour or so trying to partition a Seagate 2TB Backup Plus using the Disk Utility on a High Sierra iMac without success! Having erased the original Microsoft formatting and trying to repartition the volume (partition button greyed out). I selected the disk to find that the partition button was operative. But the partition circle showed a very small partition (disk1s1) with “unknown” format which I couldn’t affect. I named two further partitions of 1TB each and tried to get them applied. It failed and said I should do a whole disk erase. I think I did but nothing changed. I had selected “Apple Partition Map” when erasing.

When I got home to myYosemite iMac with Disk Utility v13 I erased the whole disk to find that it had automatically set the Partition Map to GUID Partition Map. I then created 3 partitions very easily.

The Disk Utility on High Sierra is not at all straightforward nor easy to use. Some hints would be helpful. HELP certainly wasn’t.

I had same issue - could not partition or erase drive as I was receiving an error:

MediaKit reports not enough space on device for requested operation.

So I found this site which I replaced disk1 with disk2 as my disc was named disk2

Disk Utility fails to erase/format an external HDD (El Capitan). "Mediakit reports not enough space on device for reques…

diskutil list

to get the name to the disk you're trying to format. The below commands assume this is "disk1", but replace "disk1" with the correct disk if it's something different.

Now unmount the disk:

diskutil unmountDisk force disk2

and then write zeros to the boot sector:

sudo dd if=/dev/zero of=/dev/disk2 bs=1024 count=1024

finally attempt to partition it again:

diskutil partitionDisk disk2 GPT JHFS+ "My External HD" 0g

I would hope that Apple would fix the formatting process so I would not have to use Terminal. But it works now, So I am good.

Sure it does.

Select the drive:

Set how many partitions:

Click on the Add [+] button once for each partition you want to add. You can set the size using the Size field.

Before you start complaining about something, it would be wise to get your facts straight. 😀

Don’t sweat it. If you have any experience with the Mac prior to El Capitan you are finding the new Disk Utility less than friendly. I may have spent more electrons complaining to Apple in Feedback about the new Disk Utility program than I have since the death of Apple Works.

Hi there,

I used El Capitan and Partitioned a Hard Drive 4 times with the intention of using time machine for 4 separate computers.

I chose GUID Partition Map and Formatted 4 partitions with 250gb format: OS X Extended (Journaled) and 1 TB ExFAT however, after backing up 1 computer, the remaining partitions were greyed out when plugging into my other mac. why doesn't it like me? I tried re-partitioning it however only with OS X Extended (Journaled) but when I tried running time machine i failed. Please Help!!