Formatting an SD card from a Mac is simple and quick thanks to the Disk Utility application. This is a commonly required task before an SD card or Micro SD card can be used as a storage medium for another electronic device, or even to remove any data stored on the SD card.
This tutorial will show you how to format an SD card or Micro SD card in MacOS with the Disk Utility app.
Note that formatting an SD card or Micro SD card will erase all data on the card, as well as set a file system format for the SD card. Thus you will want to copy or backup any data on the SD card that you wish to preserve. If you’re aiming for maximum compatibility for use with most cross-platform devices, you’ll likely want to format to ExFAT, but you can also choose MacOS / OS X formats, or older FAT formats as well.
How to Format an SD Card in Mac OS
Remember, this erases all data on the target SD card. Backup any important data before going further.
- Connect the SD or microSD card to the Mac *
- Open Disk Utility, found in /Applications/Utilities/
- Locate and select the SD card in Disk Utility from the left sidebar, then click “Erase” in the toolbar
- Give the SD card a name, then choose the file system format you wish to use for the SD card (ExFat is typically the most compatible for SD card use), then click on the “Erase” button
- Let the format process complete, then click the “Done” button when finished
- Eject the SD card / Micro SD card when finished to use it elsewhere
Regardless of how you format the SD card or Micro SD card, when finished it will show as visible in the Disk Utility drive list, and in the Finder as well.
Once formatting has completed you are free to use the SD card as you want, ready for use in another electronic device, or even if you wish to write an img or iso to the SD card for something like building a Raspberry Pi.
In terms of choosing a file system format when formatting an SD card, it’s largely a matter of what the intended use is. ExFat, FAT, and NTFS are generally broadly compatible and offer solutions for for both Mac and Windows PC compatibility, whereas selecting MacOS and OS X as the format are pretty much Mac compatible only. Most SD cards come pre-formatted as some variation of FAT, and ExFat generally works for what most electronic devices that use SD cards.
You can also set security measures for the SD card if desired, but doing so would make it unreadable by something like a digital camera, Raspberry Pi, smartphone, security camera, or most other devices you might be aiming to use an SD card with. Thus while you’re free to encrypt the SD card like any other storage medium, it’s generally not recommended unless your intention is to keep it exclusively for Mac use and as an encrypted data storage device.
The approach covered here obviously focuses on formatting an SD card from Disk Utility in Mac OS, but if you’d rather use the Terminal for whatever reason than you can use diskutil to erase and format from the command line as well.
* Many older Macs include an SD card reader, but most new model Macs do not have an SD card reader built-in, however you can get a USB SD card reader for around $12 on Amazon (or get a USB-C SD card reader if the Mac has only USB-C ports).