Ubuntu – SanDisk Extreme PRO SDXC 128GB Won’t Mount

14.04macbook promountsd card

Macbook Pro early 2013, Ubuntu 14.04 (latest updates as of March 30th 2016). Everything works in OSX. A regular 2GB SD card worked in Ubuntu.

When I plug it in it shows up in /dev as mmcblk0.

When I attempt to mount it:

domenic@mac:/dev$ sudo mount -t exfat mmcblk0 /media/domenic/thing/
[sudo] password for domenic: 
FUSE exfat 1.0.1
ERROR: exFAT file system is not found.

But I have fuse installed:

domenic@mac:/dev$ sudo apt-get install exfat-fuse
Reading package lists... Done
Building dependency tree       
Reading state information... Done
exfat-fuse is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 7 not upgraded.

I have also tried a variety of file-system formats, and I have also tried varying sizes of disk partitions to eliminate these cases.

The solution shown here and here did not work for me as they simply recommend installing the fuse tools.

Here is what gparted sees. It will not create a partition table for this disk in any format:
gparted display

Here is the output for fdisk -l:

domenic@mac:/dev$ sudo fdisk -l
[sudo] password for domenic: 

WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.

Disk /dev/sda: 251.0 GB, 251000193024 bytes
255 heads, 63 sectors/track, 30515 cylinders, total 490234752 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x9f793f3f

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1      409639      204819+  ee  GPT
Partition 1 does not start on physical sector boundary.
/dev/sda2   *      409640   411854951   205722656   af  HFS / HFS+
/dev/sda3       411856896   419854335     3998720   82  Linux swap / Solaris
/dev/sda4       419854336   490233855    35189760   83  Linux

Disk /dev/mmcblk0: 127.9 GB, 127864930304 bytes
4 heads, 16 sectors/track, 3902128 cylinders, total 249736192 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/mmcblk0 doesn't contain a valid partition table

Best Answer

Having the card with a GPT partition table and ExFAT is the culprit. If I zero my USB flash device, then put it into the Mac, the format popup lets me choose between Apple / GUID / MBR. If I keep the default of GUID (GPT) now together with exFAT, I get the exact same behaviour on my Ubuntu 16.04LTS as you describe. This combination can only be read by Mac, but not Windows or Linux at the moment.

So you have to use Linux to make a readable exFAT partition as a first step.


sudo fdisk /dev/mmcblk0 and make a new partition table in MBR format with o,n,p,1,Return,Return,t,7,w to make a new MBR drive with a partition of type 7 (NTFS/exFAT) which spans the full medium.

Now, from Ubuntu, do mkexfatfs -n YourVolumeNameHere /dev/mmcblk0p1.

Test SDCard under Ubuntu by mounting it (eject/reinsert should be enough), writing to it and if you like, with GParted. After that, boot to OSX and test the card again there for functionality.

Now it should work under all systems. I have tested it with a USB stick for Ubuntu 16.04LTS, Windows 10, and Mac OS X El Capitan.