I had similar problems with my Sandisk 64GB micro sdxc when I attempted to mount the card in my Samsung I9300 International version. After formatting the card with my Windows 7 operating system my phone displayed the following message:
“SD card is damaged. Try reformatting it.”
The solution to my problem was to format my SD card in FAT32 instead of exFAT.
I did this using the following method devised by http://forum.xda-developers.com user lynkdead
CONSEQUENCES OF METHOD: 1.) this process will erase all data on the card.
2.) you will no longer be able to transfer files larger than 4gb to the card
Place the card in your PC’s card reader and determine the drive designation (i.e., G:, H:, etc.)
Download the fat32format utility in GUI version from here: http://www.ridgecrop.demon.co.uk/guiformat.exe. Click on the picture to retrieve the file.
Launch the guiformat.exe.
Choose the drive that corresponds to your SD card.
Choose the size of the SD Card you are formatting.
Check the Quick Format box.
Enjoy your usable SD card