When I insert my 64GB SanDisk Micro SDXC Card into my 2012 MacBook Pro (in a MicroSD/SDHC/SDXC Adapter that works with other Micro SD cards), a popup dialog informs me that "The disk you inserted was not readable by this computer." The card works properly in my phone; it was formatted by a Galaxy S3.
$ sudo fdisk /dev/disk4 indicates that the computer can, in fact, read the "disk"; it contains a single partition formatted to Win95 FAT32L. Presumably the "L" indicates the LBA version of FAT32.
Is OSX not able to read large FAT32 volumes? Is there a way to remedy this? Or is the problem that OSX cannot properly deal with SDXC cards?
Update: The volume appears to be exFAT. See my answer for more info.
Best Answer
Most Android phones format exFAT SDcards incorrectly, the BlackBerry Priv being the only one I know that does it correctly. All other Android devices create a partition of type 12 (sometimes referred as hexadecimal "c") instead of 7. The android device actually ignores the partition type, so if you set it to 7 then the sdcard will work fine everywhere. There are many options: