...
- find your SD cards disk and unmount it
diskutil list
diskutil unmountDisk /dev/<diskname> //mine is diskutil unmountDisk /dev/disk2 - We are going to write 0's (zeros) 100 MB
sudo dd if=/dev/zero of=/dev/<diskName> bs=1m count=1000 //mine is sudo dd if=/dev/zero of=/dev/disk2 bs=1m count=1000The above step can take a couple of minutes with out feedback from the command line (mine took just over one minute)
...
The copying might take a minute or two, depending on your machine. You will not see anything on the screen until it is done.
...