Not enough space to Partition when formatting in Mac OSX 10.11 (El Capitan)

I have WD My Passport Ultra 259F Media portable hard drive. I’m trying to format it in exFAT or FAT32 so it can be used on both Windows and Mac OSX. I am currently on Mac OSX 10.11 (El Capitan). When I try to Partition it using Disk Utility, I get an error message that says unmounting disk. MediaKit reports not enough space on device for requested operation. Operation failed…
Is anyone else having this problem? Thanks.


Make sure you are following the instructions listen on the link below.

I had the same problem with reformatting using the WD instructions as pointed out by Hamlet. I am using a My Passport Ultra with a Macbook running Mac OS X 10.11.15 (El Capitan).

I got around the issue by using the Erase command instead of Partition. This allowed me to do exactly what the Partition command does, erasing anything on the drive (there was previously nothing on the drive and was brand new), formatting in MS-DOS(FAT), and using the Scheme: GUID Partition Map.

It worked! Thank you so much Badidar.

That is a problem with the new OSX 10.11 when it introduce. You would have to erase the new drive first before you able to partition or format the drive using a different drive format. I encounter that problem with my bashscript to format the drive until 10.11 will not run the script.