Cannot Use the Disk Utility to Create Two Partitions on External HDD with High Sierra I just bought a new external hard disk and I want to create some partitions. I am using the Disk Utility app in an High Sierra OSX MacBookPro.

However, the "partition" option for my hard drive is greyed out, therefore I cannot go ahead with the partition operation.



Although, when issuing the command diskutil partitionDisk disk2 2 MBR fat32 "PART1" 80% fat32 "PART2" 20%, I am able to partition, I cannot directly operate through Disk Utility.

How can I do this using the Disk Utility application?
The Disk Utility application can partition the external drive, if you use GUID Partition Map scheme. 

Below is an example using a 16 GB flash drive.


Erase the drive.


Partition the drive.


Erase the first partition.




The results are shown below.