Partitioning Flash drives and Disk Utility

As usual I hope this is the right section! I bought two Kingston USB 3.0 flash drives [16GB] as a home for a couple of image [.dmg] files. One of these files is around 7GB in size, however, and Disk Utility won't let me partition above 5.40GB. Why 5.40? No idea. Every time I resize it just retains the blue colour for the allocated 5.40, referring to everything above it in white as 'available space'. It's driving me crackers [no pun intended]. I've rehearsed all my 'how to create partitions on flash drives' stuff. I just don't see what I'm doing wrong - or if indeed the fault lies with me and not Disk Utility or even the new drive in some way. I've had this before once or twice but managed to make it go away [can't remember how].

I should mention that I formatted them to Mac OS Extended [journaled] with no problem. I also scanned them with that H2testw programme on my old Windows laptop to make sure everything was ship-shape and Bristol fashion. Both passed with flying colours. I do hope someone can help. Thanks.

Try formatting again. That program may have reformatted FAT32. After formatting Mac OS Extended (Journaled) go into Partition then Options and make sure GUID is selected, then partition.

harryb2448 said:

Try formatting again. That program may have reformatted FAT32. After formatting Mac OS Extended (Journaled) go into Partition then Options and make sure GUID is selected, then partition.

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Hello Harry. When you say 'that programme' do you mean H2testw? Not possible. I deleted the test files it leaves before removing it from the Windows drive then reformatted it to Mac immediately upon inserting it on my Apple machine. I've refomatted several times since. Everything reads as it should on Disk Utility ['Mac OS Extended (journaled)'] so I've no reason to think it's still using FAT32.