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A new USB Flash memory viewed in Disk Utility has Partition Type FAT and Type is also FAT.

I want to use this device for my tar backups and I have no need for portability to Windows so I decided to click on Format Volume to convert it to ext4. The Type changed to ext4 but to my surprise Partition Type is still FAT, specifically W95 FAT32 LBA 0x0c.

I can click Edit Partition to change this and there are many choices. Does this choice matter, or in other words, should I also change Partition Type and what should it be changed to? A couple of choices are Linux and Linux Extended.

Edit Interestingly, when I selected Linux for the Partition Type the program proceeded to run the hard disk for about 10 minutes. Scary, I know. The hard disk is run even though the utility clearly shows that it is the USB drive that has been selected for information display and modifications. Then it reported that there was some sort of failure but there was not enough memory to report the problem to developers.

H2ONaCl
  • 10,039

2 Answers2

13

I was having a similar problem. I resolved this by first unmounting the partition via cli:

sudo umount /dev/sdb1 (or whatever your usb is)

Then formatting the partition for ext4 (it cannot be formatted while mounted/in use):

sudo mkfs.ext4 /dev/sdb1

That should do the trick, worked for me.

Lukashka
  • 237
2

One solution is to choose Format Disk and set it to no partitions. Then set the entire volume to ext4. Copy the tar file to the Flash device and use diff to verify.

H2ONaCl
  • 10,039