I'm trying to rename a 16GB SD card (Untitled) using a MacBook Air but the Disk Utility won't let me rename/erase/reformat it. I am able to open the device and see all of its content but cannot rename it. The reason I want to rename it is so that 3rd party apps on an Android Smartphone can write to the SD card. Right now, only the native Android file manager can write to the Sd card. Inserting the micro SD card into the adapter and then inserting the adapter into the card reader of the MacBook Air puts the device on the desktop. When I click on the label name, it turns blue but I still can't change the name.
sometimes there is a tiny tab on the SD adapter (or standard SD card) that prevents read/write to the card. Make sure this isn't set to "lock."
Otherwise: What version OS are you running? Can you write or delete files from the card?
Open terminal and use
diskutil list to find the disk number of the SD card. Then change disk2 below to the number, making sure you physically disconnect any disks you can't afford to erase if you make a mistake with the numbers.
diskutil eraseDisk MS-DOS UNTITLED disk2