This just happened to me in my brand new macbook pro 2012. My Sandisk SDHC Extreme Pro card can be read but I can't delete files. Has any one had this happened to? please help. I have searched online and very little threads on this topic, some people had this issue and even after reformatting card persisted. In any windows computer this is not an issue with the same exact card. It is not the lock tab on the side this is not locked the info shows FAT32 read only. Why should this be a problem I thought that MAC was ok with FAT 32 cards. Frustrated.