32GB Sandisk Micro SD suddenly stopped being recognized by Galaxy S3 phone

What I did with mine was I just left the card in my Galaxy S3 and it eventually was able to read it again. When it did, I immediately connected it to my PC and transfered all the files over. I will now format it a couple times and return the card to Costco. I would recommend this to those of you who didn’t have backups of your files prior to the card going to ■■■■. Give it some time and keep monitoring the device and backup if/when your card is readable.