Why won't Disk Utility format my 64GB microSD card as MS-DOS/FAT?

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Level 1

4 points

Why won't Disk Utility format my 64GB microSD card as MS-DOS/FAT?

macOS Sierra 10.12 on late 2013 15" MacBook Pro

Class 10 SanDisk 64GB microSD

Mounting microSD using SD adapter

I have formatted my SD card using SDFormatter. By default, SDFormatter formats 64GB microSD cards as ExFAT. I then open Disk Utility and try to erase and reformat the card as MS-DOS (FAT) and Disk Utility returns the error message "Name invalid." It's definitely not the name—I've tried "boot," "a," and so on. I would try to partition the card, except the "Partition" button in Disk Utility is grayed out, i.e. I can't click on it.

I need the microSD card to be formatted as FAT32 so that I can use it for my Raspberry Pi.

Any suggestions?

MacBook Pro with Retina display, macOS Sierra (10.12)

Posted on Mar 31, 2017 9:00 PM

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Answer 1

Drew Reece

Level 6

10,684 points

Apr 1, 2017 9:17 AM in response to kaz-k

Wikipedia claims 2Tb is supported for FAT32 ?

https://en.m.wikipedia.org/wiki/File_Allocation_Table

I suspect if it is for a Raspberry Pi then a Linux format would be better option - ext3, ext4 etc. The Pi can partition & format volumes. The Mac can read them if you install OS XFuse with ext2/3 support.

If you hope to boot this on the Pi then you'd be better off using etcher or 'dd' to write the partition table. You simply expand the system partition on next boot. Only the boot partition is FAT, and a few hundred MB is sufficient, the system partition will probably be ext3.

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Answer 2

kaz-k

Level 9

51,264 points

Apr 1, 2017 1:10 AM in response to chsgray

I need to format as exFAT if your SD card is more than 32GB.

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