Before reformatting the corrupted SD card, make sure you have recovered data from that SD card. If not, try iBoysoft Data Recovery to do an SD card data recovery.
After backing up the data, it is time to reformat your SD card on Mac with following methods:
Option 1: Format your SD card with Disk Utility
Step 1: Open Finder, go to Applications folder and Utilities folder, launch Disk Utility.
Step 2: Select the SD card at the left sidebar and click on the Erase button at the top toolbar.
Step 3: Give the SD card a name.
Step 4: Select file system.
As SD card, we usually select exFAT or MS-DOS(FAT) as file system.
Disk Utility won't let you format 32GB and smaller SD card as MS-DOS(FAT) file system. You can see the option, but it's grayed out. That's because exFAT is the format you should use instead.
Step 5: Select a scheme: GPT (GUID Partition Table) or MBR (Master Boot Record).
Step 6: Set security options if you want to securely erase all data.
Use the slider to choose how many times to write over the erased data, then click OK.
Step 7: Click on the Erase button to format your SD card.
If you see "Operation failed", it means Disk Utility cannot format your SD card, try solution 2.
If you formatted a wrong SD card, try iBoysoft Data Recovery to recover data from that SD card.
Option 2: Format your SD card with Terminal
If Disk Utility is unable to format the SD card, things will be more complicated. You have to force to erase the SD card with Terminal. This method is also suitable for an experienced user who is fond of using Terminal to do work on their Macs. Follow the steps below to format the SD card:
Step 1: Go to "Applications > Utilities > Terminal".
Step 2: Enter the following command into Terminal: diskutil list
Step 2: You will get a list of all your connected drives to your Mac. What you need to note down is the specific identifier for the SD card you want to format. Once you find the proper drive to erase, just copy the identifier so you can use it for the next command.
Step 3: Type in the following command into Terminal: diskutil eraseDisk FAT32 diskname diskidentifier. Replace "diskname" to the new name you want to for the SD card. And change "diskidentifier" to the disk identifier of your card.
For example: sudo diskutil eraseDisk FAT32 MYSD MBRFormat /dev/disk2
Step 4: Press Enter to format your SD card.
If your SD card won't format by Terminal command, try solution 3 as below.
Opition 3: Format your SD card with the third-party application
Download a professional SD card format tool called SD Memory Card Formatter to format your SD card.
If your SD card is still not working for reformatting, please make the following checks:
- Check if your SD card is Locked
- Check if your SD card is write-protected
- Try a different SD card reader