Hello My Toshiba HDD in my Mid2012 MBP was going incredibly slow (virtually unusable). So I purchased a SanDisk SSD Plus 240Gb from Best Buy. I replaced the Toshiba in the main bay with the SanDisk and then connected my bootable drive with Yosemite, selected the bootable drive as the start-up disk then went into Disk Utility to format the SSD before trying to install Yosemite into the drive. I repeatedly get the error: "Volume Erase Failed with Error: File System Formatter Failed" I can't partition to anything Mac partitions either. I can, however, format the drive into MS-DOS without error. The drive shows GUID, SMART Verified etc... I am not sure what to do but I can't use either drive now. Has anyone had experience with this? I have searched all over Google and this forum but can't seem to find this particular problem. Am I searching for the wrong terms? Any Help At All would be greatly appreciated. Thanks!