My SD card does not come up on my Mac mini

If this is an SD card from a camera?

Many camera makers use odd card formats that do not mount like normal external drives on Macs, This has been the case for years. Unlike computer storage manufacturers, camera makers never agreed on common formats. I have Nikon cameras and the cards do not show in the Finder of any of our Macs.

However, the good news is the you have an Apple app already on your computer that can translate the odd-ball SD card formatting. It is Image Capture and I use it all the time. See:

Transfer images in Image Capture on Mac - Apple Support

It lets you view photos and videos that are on the SD cards and easily transfer them to your Mac. Its a simple interface, Here is how the card from my DSLR shows in Image Capture:

Camera makers usually furnish software that does the same thing, but they usually have a very steep learning curve.

1. Make sure the SD card is firmly seated in the slot.
2. Test some other SD cards in the slot.
3. Check your Finder preferences.
4. Restart the Mac Mini.

If none of those help, then you may need to get and use an external USB card reader.

Allan Jones wrote:

If this is an SD card from a camera?

Many camera makers use odd card formats that do not mount like normal external drives on Macs, This has been the case for years. Unlike computer storage manufacturers, camera makers never agreed on common formats. I have Nikon cameras and the cards do not show in the Finder of any of our Macs....

That is quite odd. Do you have an older Nikon? What make/speed grade card(s)?

I recently inserted the Nikon formatted SD Card from my D7500 when I needed to copy a firmware update file and it mounted just fine in Finder. This was with plugging into an OWC TB4 dock and my M1 MacBook Air. Also, mounts with a USB SD/micro SD dongle directly connected.

Older yes, a D5000, and both my Macs are still on Mojave for compatibility reasons. I'm on the road without the Nikon so cannot check the card specs. I was aware of the possible age issue because the OPs equipment line shows OS 10.10, which definitely had the problem.

I mentioned that because we are not usually supplied with the card type and, if a camera, which mac/model.