Q: SD card slot not recognizing card

Do you have another SD card you can try to determine if the problem is with the card or the slot?

When you insert your SD Card, see if you can see it in Disk Utility.  If you can see it there, then format/erase that SD Card in MAC OS Extended Journaled if you're not using it for anything else or use FAT or exFat if you'll be using it with Windows.  FAT if you're using it for your Digital Camera.

Thanks for posting.  My SD card slot was not working.  Then, I opened up Disk Utility and all of a sudden my card is recognized by all my programs.  GENIUS!