Morning folks, I have a 2009 Mac that I am looking to sell. I followed the instructions to clear the 'disk utility' but not sure if I logged out of iCloud etc. first. I want to reinstall macOS so I can check, but when I go on this it tries to put it onto 'OS X Base system' but it is saying that the disk is locked and so can't get past this stage.
Any advice would be appreciated???
Any advice would be appreciated???