I am posting on behalf of my sister. She has a Mac Mini and a WD Passport external Hard drive. I have been trying to walk her through reformatting it but nothing is working. I'm looking for some advice. The hard drive is already formatted in Mac Os Extended. When the disk utility recognizes it the drive is read only. The disk utility gives no options for formatting under the erase tab. The volume scheme under the "partition" tab is also all "greyed out" and unclickable. In an attempt to format from a pc I found the drive and tried to format thru the disk management program. It also gives no options for formatting. Obviously something isn't write with the drive but I have no idea how to go about figuring it out.