Since switching to Mac I haven't been able to edit anything on my externals. I can copy data onto it, but nothing else. I've just noticed that I've formatted it to NTFS, is this why? Do I have to re-format in FAT32 (I think that's it's name), the reason why I formatted to NTFS when I was using windows was because I wanted to transfer files over 4gb, how do you guys do this on a mac? If that's the problem.