Before you can use a microSD card, it has to be formatted. While many do come pre-formatted out of the box, it’s still best practice to format it yourself before using it.
To keep it compliant with SD Association specs, which minimizes the risk of your camera having problems with it, it’s important to choose the correct filesystem to format it with.
So here’s a guide on how to format microSD cards on Mac.
First is the quick version; after that is a more detailed step-by-step guide. And I’ve also included an alternative approach using the SD Association’s SD card formatting app that provides a risk-free way of setting the card up properly.
How to Format SD Cards on Mac: The Quick Version
- Connect your microSD card to your Mac using a microSD memory card reader or adapter
- Open Disk Utility app
- Select your SD card
- Choose Erase function
- Enter SD card name (optional)
- Choose filesystem format. If 64GB or larger, choose exFAT. If 32GB or smaller, choose FAT32.
How to Format microSD Cards on Mac: The Detailed Version
That was the quick version. Here’s the more detailed version.
The good news is that you don’t have to download some expensive app to do it—everything you need is already there as part of the macOS operating system.
First, though, I should point out that if you’re using your microSD card in a camera, it’s best practice to format the card in the camera itself. That way, the camera can set it up how it wants and expects it to be, and it reduces the risk of filesystem issues interrupting your shooting. All cameras have a “format card” function (sometimes it’s called something similar). Some even have a low-level formatting option, which is a more thorough (but also slower) process.
But if you want to go ahead and use format your microSD card on your Mac, here’s how to do it. Before starting, make sure you’ve saved any data you want to keep from the memory card, because formatting the card will delete all of the data on it.
1. Connect your microSD card to your Mac
There are different ways to do this. Some Macs come with a built-in SD slot. If you have one of those, you can insert the microSD card into an inexpensive microSD-to-SD adapter and then put that in the slot. Many microSD cards come with the adapter included.
- Micro SD to SD card adapter
- Built-in write protection switch
If your Mac doesn’t have a built-in SD card slot, you can use a memory card reader that plugs into the computer’s USB port. An inexpensive microSD card reader will work fine, although you can also get high-end readers that have faster performance. Make sure to get a reader with the right kind of USB plug for your Mac (newer Macs use USB-C; older Macs have USB-A or both).
- Faster USB 3.0 Transmission: UGREEN USB to SD Card Adapter supports up to 5Gbps data transfer rate, which…
- Simultaneous Reading&Writing: This SD Card to USB is able to read and write SD/microSD cards at the same…
Another alternative is that some cameras can function as a memory card reader when connected to a computer, but that depends on the specific model–not all cameras can do this.
2. Open Disk Utility App
Disk Utility is part of the macOS operating system, so you don’t need to download or install it. You can find it in your Applications folder under the Utilities subfolder (Applications > Utilities > Disk Utility). Or you can use Spotlight (the magnifying glass icon at the top right of your screen) to search for it by clicking on the icon and then typing “disk utility”.
3. Identify Your SD Card
On the left side of Disk Utility’s screen is a list of the various drives in your Mac and connected to it. So it will show your Mac’s internal drive as well as external drives. The microSD card should show up in the External section. If it hasn’t been formatted before, it might have a name like “NO NAME” or “UNTITLED”. If you click on it, you’ll see how much storage it is. Make sure that it matches what you expect—that is, if you’re inserting a 64GB SD card, make sure the capacity is showing as 64GB or close to it. If you see something like 1TB instead, you’ve selected the wrong drive from the list.
4. Choose Erase Function
From the list of functions at the top, choose Erase. You’ll get a popup warning you that you’re about to delete everything on the card.
5. Enter microSD Card Name
In the Name field, you can assign a name to the card. This is an optional step—it will work just fine if you leave it as NO NAME or UNTITLED—it’s just a convenience issue to display a friendly name when you’re viewing it in Finder or making sure you’re importing from the correct card when ingesting images into Lightroom, for example. Keep the name short and simple—any long names or special characters will get rejected. Perhaps something like SDCARD1 or GOPRO, for example.
6. Choose the Filesystem Format
Under the Format drop-down menu, you have several options. The only ones we’re interested in here are MS-DOS (FAT32) and ExFAT. Which to choose depends on what size storage cards you’re using. If your SD card is 64GB or larger, choose ExFAT. If your SD card is 32GB or smaller, choose MS-DOS (FAT32). 
7. Hit Erase
It will say it’s unmounting it, and then, after a few moments (or perhaps a little longer), you should get a message that the process is complete.
And with that, you’re done, and the card is ready to use.
As I mentioned earlier, it’s best practice to format memory cards in the camera, but if you want to format your SD card on your Mac, this is how you do it.
Things to Know
Older versions of macOS don’t support exFAT. Specifically, exFAT support was added to macOS in version 10.6.6, which was Snow Leopard released in 2009. If you have any of the newer macOS versions released since then–including Lion, Mountain Lion, Mavericks, Yosemite, El Capitan, Sierra, High Sierra, Mojave, Catalina, Big Sur, or Monterey–those all have native exFAT support baked in.
It’s a good idea to be extra careful when selecting your microSD card from the list. You don’t want to accidentally format another drive.
When you format a memory card, you should be prepared for everything to be deleted from the file. But in reality, it might still be possible to recover files from the card even after formatting. If you find yourself needing to try, take a look at my post on how to recover files from SD cards.
I’ve put together a guide to the different types of SD cards separately.
Alternative Method: SD Card Formatter
There’s an alternative method to formatting a microSD card on your Mac that involves downloading a free SD card formatter app provided by the SD Association. The SD Association is the organization that designs and controls the SD specification, and their app is specifically designed to conform perfectly to the official specifications.
It’s very simple to use, with just a single screen that looks like this:
It does have some small benefits over using Disk Utility. One is that it automatically detects what is and isn’t an SD card (or microSD card), and it won’t make non-SD cards (or non-microSD cards) available. This means there’s less chance of accidentally erasing the wrong drive, which is a useful safety precaution.
Another is that it will automatically detect the size of the card and choose the appropriate filesystem. If you insert a 64GB card, it will only allow you to format it to SDXC specifications using exFAT. So it takes out any risk of selecting the wrong option. And they do provide this warning:
It is strongly recommended to use the SD Memory Card Formatter to format SD/SDHC/SDXC Cards rather than using formatting tools provided with individual operating systems. In general, formatting tools provided with operating systems can format various storage media, including SD/SDHC/SDXC Cards, but it may not be optimized for SD/SDHC/SDXC Cards, and it may result in lower performance.
It’s free, and you can find it here. There are versions for Mac and Windows.
How to Recover Data from a Memory Card
If you’ve accidentally deleted videos or photos from your camera’s memory card, there’s still a good chance that you can recover it.
The first thing to do is stop using the card. The more data is overwritten, the harder it will be to recover what you’re after.
The next thing to do is to download data recovery software to scan the card to find recoverable data. There are a number of good options for doing this. I go into more detail separately in these posts:
- Best Free Data Recovery Software for SD Cards
- How to Recover Deleted Photos from SD Card: SD Card Recovery Options (this is more comprehensive and includes paid software)
(Although the titles of these posts refer to SD cards, they apply equally to other types of memory cards (and external hard drives and thumb drives, for that matter.)
Do you need to install an app to format a microSD card on a MAC?
It’s not required to buy or install extra software to format SD and microSD cards on a Mac. The Disk Utility app that comes included as part of macOS can be used to format memory cards.
The benefits of installing the free SD Card Formatter app from the SD Association are that it eliminates the risk of accidentally formatting the wrong drive, and it conforms perfectly to the official SD specifications.
What Format Type should you choose when formatting a microSD card on Mac?
For SD and microSD cards that are between 4GB and 32GB, choose MS-DOS (FAT32). For SD and microSD cards that are 64GB and above, choose ExFAT.
Can data be recovered after accidentally formatting a microSD card?
It might be possible to recover data after accidentally formatting a microSD card. For that, you will need to download and install a data recovery app.
Memory Card Tools
Here are a few other related tools I’ve put together that can be useful when working with memory cards and data rates.
Converting Mbps to MB/s & X Speed Rating to MB/s
Another related and common calculation that often needs to be done when working with memory cards is converting the convention for measuring video bitrate (Mbps, Mb/s, or megabits per second) to the convention for measuring the speed of memory cards (MBps, MB/s, or megabytes per second).
So I’ve put together a simple calculator for that separately. You can find it here:
- Convert Megabits Per Second to Megabytes Per Second Calculator
- Convert Memory Card X Speed Rating to MB/s
Memory Card Size Calculators
If you’re trying to figure out what size memory card to buy, it can be useful to know how much video footage from the camera you can fit on a card. Here are a few tools that can be useful for that:
- Video Bitrate vs Memory Card Size Calculator
- How Much 4K Video Can 128GB Hold?
- How Much 4K Video Can 256GB Hold?
- How Much 4K Video Can 64GB Hold?
Working with Memory Cards
Here are some related posts for making sense of memory cards and working with them.
- Fastest SD Card Speed Tests. With cameras getting improved 4K, 5K, and even 8K video recording and burst shooting features all the time, some of them need the write speeds that only the fastest SD cards provide. So here’s a roundup of the fastest SD cards based on my independent tests.
- Fastest MicroSD Card Speed Tests. Need a fast microSD card? If you’re shooting 4K, 5K, or 8K video, high-speed burst-mode photos, or some other demanding use, speed matters. These are the results from my independent speed tests of the fastest microSD cards.
- Types of SD Cards Explained. There are several different types of SD cards, as well as multiple speed rating systems and cryptic codes. Here’s a rundown of what the differences are.
- UHS-I vs UHS-II on microSD & SD Cards. Wondering what the difference is between UHS-I and UHS-II with SD and microSD cards? Here’s an explanation.
- A1 vs A2 SD cards and microSD Cards You might have seen new A1 and A2 speed ratings on some of the newer SD and microSD cards. So what do they mean? And when should you take notice of it?
- SD Card Formatter App for Formatting, Wiping & Repairing SD & microSD Cards. Here’s a guide to using the SD Association’s official SD Card Formatter for preparing your SD and microSD cards for use.
- How to Format SD Cards on Mac. Here’s a step-by-step guide for formatting both SD and microSD cards.
- Best Free Data Recovery Software for SD Cards. Here’s a rundown of the best free data recovery software to use if you’ve accidentally deleted photos or videos from your SD card.
- How to Rover Deleted Photos from SD Card: SD Card Recovery Options. All those photos you took have disappeared from the SD card. The good news is that there’s still a good chance you can recover photos from the SD card. Here’s what to do. Includes free and paid SD card recovery options.
- It is technically possible to format the SD card with the other filesystem (e.g., a 32GB card with exFAT or a 128GB with FAT32), but it can be risky to do that with some cameras. Some cameras will throw an error if the card isn’t formatted with the system it expects as defined in the SD Association’s specs. So if you do want to go against the specs, it’s worth making sure that your camera will accept it before heading off to shoot.
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