How do I check the health of my micro SD card on my Mac?

A micro SD card, sometimes referred to as a microSD or uSD card, is a type of removable flash memory card used for storing photos, videos, music, and other files on small, portable devices like smartphones, tablets, and action cameras. They are miniature versions of regular SD cards. The most common uses are in mobile phones, digital cameras, handheld GPS devices, media players like the Nintendo Switch, and drones. As these devices rely on micro SD cards to store important files and data, it’s critical to periodically check the health of the card to avoid potential data loss or corruption.

Regularly monitoring the condition of your micro SD card can help identify issues early and prevent bigger problems down the line. This allows you to proactively fix minor issues or replace the card before it fails completely. Checking card health will be covered in detail throughout this guide.

Signs of a Failing Micro SD Card

There are a few key signs that indicate your micro SD card may be failing or experiencing issues:

Slow transfer speeds – If you notice it is taking much longer than usual to copy files to or from the SD card, read/write speeds have slowed down significantly, this often indicates the card is having issues.

Frequent errors when reading/writing data – You may get frequent error messages when trying to access files on the SD card. The card may be unable to read data written to it. This points to problems with the card.

Unreadable files – One of the most common signs of a failing SD card is corrupted files. You may find files on the card appear corrupted or cannot be opened. The card cannot reliably read data stored on it.

Difficulty formatting – If you have trouble reformatting the SD card, it could mean the card is damaged. A healthy card should format without issues.

Other signs include the SD card not being recognized by your device, apparent loss of storage capacity, or the card feeling warm when used. If you notice any of these issues, it likely means the card is failing.

Using First Aid on Mac

One way to check the health of your micro SD card on Mac is by using the built-in First Aid tool in Disk Utility.

To use First Aid:

1. Open Disk Utility on your Mac. You can find this by searching for it in Spotlight or navigating to Applications > Utilities > Disk Utility.

2. In the sidebar in Disk Utility, select the micro SD card drive. This will likely be labeled with the capacity, brand, or typically “NO NAME”.

3. Click on the “First Aid” button at the top of the Disk Utility window.

4. First Aid will check the disk for errors and attempt to repair them. Let it run to completion.

5. When finished, you can view the messages from First Aid by clicking “Show Details”. This will indicate if any errors were found and if repairs were successful.

If First Aid is able to repair your disk, the micro SD card may be restored to proper working order. However, if it finds errors that cannot be fixed, your SD card may be damaged and need to be replaced. Using First Aid regularly can help catch minor problems before they become major ones. However, its effectiveness in resolving major issues can vary.

See a walkthrough guide at

Check Health with Terminal

You can use Terminal on your Mac to get detailed information about your micro SD card and check its health. Here’s how:

1. Open Terminal. You can find it by going to Applications > Utilities.

2. In Terminal, type the following command and press Enter:

diskutil info /Volumes/NAME_OF_CARD

Replace NAME_OF_CARD with the actual name of your SD card volume.

3. This will show you information like:

  • Device identifier
  • Total disk capacity
  • Volumes in use
  • Available disk space

4. Check if the capacity matches the advertised capacity for your SD card. Any major discrepancies could indicate a problem.

5. Also look at parameters like “Media Name” and “Medium Type” to verify it is detected properly as an SD card.

6. The output will also show you if any errors were detected on the disk. If so, your SD card likely has integrity issues and should be reformatted or replaced.

Using Terminal gives you more detailed technical insight into your SD card’s status and can help identify problems not caught by other methods.

Using Third Party Tools

In addition to the built-in Disk Utility tool, there are several third party applications you can use to check your micro SD card’s health on a Mac:

SD Card Formatter

SD Card Formatter ( is an app from the SD Association that tests and formats SD cards. It scans for bad sectors and provides a report on your card’s health. The main downside is it will erase all data on your card.

SD Card Test

SD Card Test ( is a free Mac app that does read/write tests to diagnose problems. It also benchmarks your card’s speeds. The interface is basic but it’s easy to use.


F3 ( is an open source tool that writes test patterns to find bad sectors. It has a simple command line interface. The major downside is you have to build/compile it yourself.

Each tool has pros and cons but they provide more detailed diagnostics than Disk Utility alone. Just be careful, as some will erase your card in the process.

Best Practices

To maintain the health and longevity of your micro SD card, follow these best practices:

Check the health of your micro SD card regularly using the methods described in this guide. Frequent health checks can help you identify issues early before they cause data loss. Memory Cards 101: A Beginner’s Guide recommends checking your card’s health every few months.

Back up important data from your micro SD card to another storage device or cloud storage. Don’t rely solely on the micro SD card for long-term data storage, as cards can fail unexpectedly. Regularly backing up minimizes the chance of irrecoverable data loss.

Consider replacing your micro SD card every few years or when you notice performance declining. Micro SD cards have a limited lifespan and will degrade with heavy usage over time. Replacing cards proactively avoids failures and data loss issues down the road.

Fixing Minor Issues

There are a couple straightforward steps you can try first before determining your micro SD card needs to be replaced. Formatting the card and deleting unused files may resolve minor performance issues or glitches:

Formatting the card erases all data and restores the file system, which can fix problems caused by corruption or conflicts. To format on a Mac, open Disk Utility, select your SD card, click “Erase”, choose “MS-DOS (FAT)” or “exFAT” format, then click “Erase” again. This will wipe the card clean.

Deleting unused files frees up storage space and clears out any problematic data that may be contributing to issues. Open your SD card on your Mac desktop and delete any unnecessary photos, videos, downloads or other files you no longer need. An overfilled or cluttered card can sometimes lead to read/write errors or slow performance.

Trying these basic troubleshooting tips costs nothing and may get your card working properly again. But if you still encounter issues after formatting and deleting files, the card likely has deeper problems and should be replaced. Back up any important data first before these steps, as formatting erases all content.

Signs it’s Time to Replace

There are a few signs that indicate it may be time to replace your micro SD card after several years of use:

  • The card is 5 or more years old. Micro SD cards have a limited lifespan and can start developing issues after prolonged heavy use over many years. The NAND flash memory cells degrade over time.
  • You are unable to fix formatting issues or errors using First Aid on Mac or the disk utility tools. If the card develops bad sectors that cannot be repaired, it likely means the card is failing.
  • The card becomes very slow and takes a long time to read/write data. As cards near the end of their lifespan, the performance degrades significantly.
  • You frequently get read/write errors, corruption, or data loss. This indicates the memory components are failing and the card is unreliable for storing data.

If basic troubleshooting steps don’t resolve performance issues or data errors, it’s generally recommended to retire the card and replace it with a new one to avoid potential loss of important data. Micro SD cards are inexpensive, so replacing a card every few years ensures you have reliable storage.

Buying a New Card

If your old micro SD card is no longer functioning properly or is damaged, you’ll need to purchase a new one. When buying a replacement micro SD card for your Mac, there are a few key factors to consider:

Reputable Brands
Stick with major, reputable brands like SanDisk, Samsung, Kingston, or Lexar when buying a new micro SD card. These brands consistently manufacture high-quality, reliable cards that will work seamlessly with your Mac.

Speed Class Rating

Look at the speed class rating marked on the card, which indicates the minimum guaranteed read/write speeds. A faster class 10 or UHS-1 card will provide better performance than a slower class 4 card when transferring files like photos or videos.

Storage Capacity
Choose the storage capacity based on your needs. A 16GB card may be sufficient for documents and light use, while a 128GB or 256GB card allows you to store far more photos, videos, music, and other files.

Buying from a reputable retailer and checking reviews can further ensure you get a high-quality, properly functioning micro SD card for your Mac.


It’s important to keep an eye on the health of your micro SD card, as a failing card can lead to lost or corrupted data. This article covered several ways to check your micro SD card’s health on a Mac. You can use the built-in First Aid tool or the diskutil command in Terminal to scan for errors. Third party tools like SD Card Formatter can also provide more detailed diagnostics.

Monitoring your card’s health lets you address minor issues before they become catastrophic failures. Replacing cards that are showing their age is wise to avoid data loss down the road. Always make sure to safely eject the card before removal to avoid corruption. Following best practices like avoiding overfilling the card and excessive rewrites will maximize its lifespan.

While a damaged SD card can be frustrating, being vigilant about performance testing and monitoring health indicators can help you catch problems early. Investing in a high quality, name brand micro SD card and taking steps to use it properly will lead to many years of reliable service.