I am trying to partition a new external drive with 4 TB capacity with MacOS 12.5.1 & Disk Utility to a Windows-compatible format (MSDOS etc.). But no matter how to "erase" the disk, I am not able to partition the disk. It always says "This volume can’t be resized." and I neither can add or remove a partition.

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How can I partition this external drive into 2 partitions of equal size in a windows-compatible format?

1 Answer 1


Maybe this GUI is not the best tool to work with disks, so here is how I managed to partition the external disk using the command line tool diskutil.

First, you need to get a list of all devices using the command

diskutil list

Then you erase your disk using the ExFAT format, like

diskutil eraseDisk ExFAT BACKUP /dev/disk3

(where you replace /dev/disk3 with your proper location), and finally you partition the disk using the command

diskutil partitionDisk /dev/disk3 2 MBR  ExFAT BACKUP1 2000G ExFAT BACKUP2 0

In the latter I use 2 partitions with the first having 2 TB of space and the second partition the rest (hence the "0").

That process seem to have worked for me ...

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