I have a 13" Macbook Air (mid 2012) running Mountain Lion. I'm trying to connect my Samsung S2 Portable External Hard Drive 320GB formatted in FAT32 to the macbook but it doesn't show up in the finder's sidebar. However, it appears in Disk Utility but when I try to mount it, it says "The disk “SAMSUNG” could not be mounted.Try running First Aid on the disk and then retry mounting."
But I can't even use First Aid because "verify" and "repair" buttons are grayed out.