Hi, I have a question about hardisk formatting. I got a hardisk, which was previously used in the other device (not MacBook), hardisk is functioned and fully tested by previous owner. I put it inside of my MacBook Pro 2010 and started Internet recovery Mode. My question is: I can not change partition map, Hardisk has currently partition map Master Boot Record. in the disk utilities in menu bar the partition is not highlighted so I can not enter inside of it to change. It is some other way how I can do it? Thank you for an advice.