How to Format an SD Card (SD Card) on Mac

Did you buy a new SD card or are you just reusing a spare one? It may be a good idea to format it first.

Formatting an SD card makes a clean slate, removing any trace of old files. It also allows you to change the file system of an SD card (new or old), allowing other devices to read and write to it, including Macs. However, there are risks, and you could lose your data or corrupt your SD card if you don’t take precautions.

If you are not sure how to format an SD card on Mac and want to do it safely, please follow these steps.

Before formatting SD cards on Mac

Before formatting an SD card in macOS, you will have to make sure you have a card reader. Some Macs have them, but many don’t.

Fortunately, SD card readers are not expensive. If your Mac doesn’t have a built-in card reader, you’ll have to buy one.

Then you have to know which file system to use. This is pretty easy to figure out. For SD cards less than 32GB, please use the file system FAT32. Cards larger than 32GB need the file system exFAT.

Once you’ve determined the file system you need, you can start formatting your SD card. The best method is to use the Disk Utility application, but there are third-party alternatives such as SD Card Formatter.

How to format an SD card on Mac using Disk Utility

You don’t need any special software to format an SD card on your Mac as you can use the built-in application Disk Utility.

Disk Utility allows you to safely format SD cards on your Mac. You can also use the tool to format USB flash drives, external hard drives, or internal drive partitions.

To format an SD card on Mac using Disk Utility:

1. Insert your SD card into the reader. If you are using a USB card reader, connect it to an available USB port on your Mac.
2. Open the Disk Utility through folder Launchpad in your Dock. You can also press Cmd + Space and write Disk utility.
3. In the window of the Disk Utility, Press the sight icon and select Show all devices.
   
4. The SD card should appear in the section External on the left: select it.
   • Unformatted SD cards will appear as UNTITLED or NO NAME. If you are not sure how to choose the correct drive, take a look at the storage capacity. It should be close to the size advertised on your SD card packaging.
5. At the top of the window, click Delete.
   
6. Give your SD card a name. Keep it short and avoid special characters and spaces to ensure maximum compatibility.
7. Then choose the file system. Choose MS-DOS (FAT) for cards less than 32 GB Y exFAT for larger SD cards.
8. Click on Delete.
9. After a few moments, you will see the confirmation that the process has finished. Press Done to go out.
   

If the card is formatted correctly, you can start using it to store important files or photos. You can also remove it from your Mac and use it on other devices that support your card’s new file system.

How to format SD cards on Mac using Terminal

If you prefer to do things the old way, you can also format your SD card using the application Terminal.

Note: You must be very careful before doing this. Commands like diskutil they will happily erase almost any drive you specify in Terminal. This is a step just for Advanced users; if you are concerned, use Disk Utility instead.

To format an SD card using Terminal on Mac:

1. Insert your SD card into the reader. If you are using a USB card reader, connect it to an available USB port on your Mac.
2. Open the app Terminal through the Launchpad in the dock. You can also press Cmd + Space and write Terminal.
3. To find the unique identifier of your SD card, type diskutil list.
4. Look up the word “external” and match the storage capacity. In this example, / dev / disk4 is the correct unit.
5. For the 32GB and smaller cards, type the following (and replace / dev / disk4 by the correct drive name):

   sudo diskutil eraseDisk FAT32 SDCARD MBRFormat /dev/disk4

6. For cards of 32 GB or more, type the following (first substituting / dev / disk4):

   sudo diskutil eraseDisk ExFAT SDCARD MBRFormat /dev/disk4

   

7. If prompted, enter your user password.
8. After a few moments, the command will finish and your SD card will be formatted and ready for use.
   

How to erase an SD card on Mac

If you plan to get rid of your SD card, you need to erase it completely first using the command dd on Mac.

This process is called reset the card, as it involves writing to the SD card with binary data (zeros and ones). This removes all data on the card, including file systems and partition tables. You can also use this tool to remove protected partitions from SD cards that applications such as Disk Utility cannot remove.

Note: This will cause irreparable data loss as it cleans up the SD card. You should only try this if you have backed up your important files and selected the correct card to erase.

To remove protected partitions from SD cards:

1. Open the app Terminal via the Launchpad.
2. Scribe diskutil list.
3. Find and write down the external drive you want to erase. The unit should be labeled as / dev / diskX, where X is the number of the drive you want to erase.
4. Make sure the drive is not mounted by typing the following (replacing / dev / diskX by the correct unit label):

   sudo diskutil unmountDisk /dev/diskX

5. To erase the drive, type the following (replacing / dev / diskX):

   sudo dd if=/dev/zero of=/dev/diskX bs=1m

6. Allow time for the process to complete. Depending on the size of your SD card, this process could take several hours.
7. The command dd will display a completion message; exit the Terminal app at this point.
8. Open the app Disk Utility via Launchpad and format your drive using your preferred file system (eg FAT32 or exFAT).
   

Formatting SD cards with the SD card formatter

If you prefer to use a third-party tool to format SD cards on your Mac, you can use the tool SD Card Formatter.

Provided by the SD Association (the body that controls the specification of Secure Digital cards), this free tool quickly and safely formats SD cards on your Mac. One of the benefits of this tool is that it will not accidentally erase drives other than SD cards.

Also, SD Card Formatter automatically detects the size of the card and chooses the correct file system. Its use is simple: select the card, the format option and the new label of the unit, and press Format.

SD Card Formatter is available for recent versions of macOS, starting from OS X 10.7 Lion. May download SD Card Formatter from the SD Association website.

Reasons why an SD card won’t format on Mac

There are a few reasons why your SD card may refuse to format on your Mac. These include:

• Malware infection
• Unsafe or inappropriate expulsion.
• The SD card has been corrupted.
• The SD card is protected by some other means.

If you suspect any of them, you can use the command dd to try to erase the card and start from scratch. However, if this fails, you may have no choice but to replace the card entirely.

Using the formatted SD card

Now that you know how to format an SD card on your Mac, you are free to use, erase and reuse it as many times as you want.

Just remember to take care of your SD cards properly, keeping them in a protective case when you are not using them. You should also try to properly eject or unmount your SD cards when you’re done. If you don’t, you could lose or corrupt your data.

However, if that happens, try the zeroing process by following the steps outlined above, and then try reformatting the SD card. If you cannot reformat it, you will have to replace it with a good quality SD card that suits your needs.

Some cards are better rated for long-term use, while others are smaller in size and have a more limited lifespan. If you are concerned about data loss on an SD card, make sure to back up your important files first.