Need some help. I am trying to password protect/ encrypt a Sandisk Extreme 128GB SDXC card...however, i'm not able to. I tried using Disk Utility and the 'partition' option is not available. only the 'erase' option is available. I tried formating via OSX extended. When then to encrypt on Finder, it tells me that 'A GUID partition Table (GPT) partitioning scheme is required'. I am not able to find how i am able to do that. Has anybody tried something similar?