My M1 MacBook Pro 2020 running macOS Big Sur won’t mount my SD card. It doesn’t show up in Disk Utility and I don’t get notification when I plug it out.
I’m sure it’s not my SD card reader since it works fine with other flash drives. Also, it’s not the SD card either because my older 2019 Mac detects it.
I’ve tried rebooting it and changing the general settings for Finder, but it still won’t show up.
It seems that the SD card isn’t detected by your Mac. You mentioned that this SD card works on another Mac. I suggest you check its format in that old Mac and see if it’s NTFS formatted. If it is, the issue is possibly caused by not having an NTFS for Mac driver on the newer Mac or the driver isn’t updated to work with your current operating system. To fix it, download and install iBoysoft NTFS for Mac.
If it’s not NTFS but a format that’s full compatible with macOS, you can back up your files on the old Mac and reformat the SD card to start afresh.
After it’s clean with a fresh file system, you can connect it to the MacBook Pro again. If it shows up, it was likely corrupted before.