Brand new iMac - SD card not working

[dadders6]

Brand new (yesterday) 21" imac Catalina (not M chip). The built in SD card isn't working. I tried two different cards from two different cameras. When I used an external reader, both cards mounted/worked. I have apple care, so I'm sure it will get figured out, I'm just curious if this is a common problem on imacs. SD slot worked fine on my previous 2011 iMac - I miss that Mac, it had a disc burner

 

[circatee]

Verify this section, in the link below..

Which SD card formats work in the SD card slot?​

Use the SD and SDXC card slot on your Mac - Apple Support

Learn how to use the SDXC slot on your Mac.

support.apple.com

 

[Fishrrman]

It may seem illogical, but sometimes the best solution is to use a USB card reader...

 

[iMas70]

I came across your thread while researching my problem. The micro-SD card from my drone isn't shown. That's in Finder and I also tried attaching a file from it in an email. Couldn't see the card there either. I tried two different card readers on my 27" iMac running Big Sur. I then tried it on my kid's iMac that has the same operating system. No luck there either. I never had a problem reading the card before. I confirmed everything is on the card while viewing it on my iPad. I have no problem reading full size SD cards.

 

[dadders6]

I inserted a non-camera SD card, formatted exfat, it DID mount/read. I then insert the previous non-working Camera (Sony) SD card and it the DID show up...so it 'magically' fixed itself, or maybe the non camera card woke it up..