My mac computor will not find the micro SD card when I plug it into the USB.

[Tommy 73]

When I plug into a few different USB ports with the Micro SD in the Micro SD adaptor on the Mac disktop I can not find any external device located. Is there a app. that I need to get or what am I doing wrong?

 

[DeadWithoutWifi]

look on the side of the adapter and see if you have that little lock thing pushed foreword. image for clarification: http://techiedan.com/wp-content/uploads/2014/04/SD-Card-lock.jpg