Mac Can't repair the disk

I was trying to open some photos on my new iMac. I inserted the card into my card reader and got the message ]: Mac can't repair the disk, followed by, You can still open or copy files on the disk, but you can’t save changes to files on the disk. Back up the disk and reformat it as soon as you can. The card IS NOT DAMAGED. I have used the same card on my MacBook Pro without issues. I was able to insert a different card (still got the same message) and open it in camera raw and Photoshop.  I couldn't convert to dng files either. Please help. Thank you

Todd M. Bloomer