My SD card slot does not does not recognize my SDHC 32GB San Disk. What is wrong???

Please refer to https://support.apple.com/en-us/HT204384 , also try other SD cards.

If you still cannot get it to read attempt restart in Safe Mode perhttps://support.apple.com/en-us/HT201262 and resetting the NVRAM per https://support.apple.com/en-us/HT204063

Good luck.

Is this a card from a camera? If so, most do not show up in the Finder because camera companies commonly use proprietary (i,e., unique to them) formatting for the cards. The Mac Finder does not natively recognize them.

If this is a camera card, there are two very easy workabouts:

1) Use the Image Capture App that came with your Mac. It will read camera cards and allow importing. Apple information here:

Transfer images in Image Capture on Mac - Apple Support

2) Download and install the image transfer/management software your camera company provides.

Try pushing a little harder to make sure that the SD Card is fully seated in the slot reader.

As mentioned, try another SD card in the slot reader.

Are you sure about this? AFAIK, all cameras use ExFat or FAT32 to format their SD Cards. Now, some *cameras* do not present as a mountable disk when connected with USB, but not SD Cards.

You're welcome!