Cannot erase SD card with Disk Utility (El Capitan) I have this SD card that I am trying to use to backup photos on a Windows computer.

After using the SD card on the Windows computer, and copying the photos back on a safe drive, I cannot erase the SD card:



And yep, in the Info window for the card, the device is listed as "read only":



I checked the Lock Tab and it's not on Lock position... What gives?
A better and simpler solution would be using the command-line.

Execute the following command to identify the mount name of SD card following the pattern /dev/diskX, e.g., /dev/disk2  

diskutil list 


Say the disk name is /dev/disk2. Now format the card to FAT32 by running the following command:

sudo diskutil eraseDisk FAT32 MYSD MBRFormat /dev/disk2