I've got an older iMac (2007) that I was going to reinstall the O/S fresh but I messed it up. I should have downloaded the install files and created a bootable install USB before the drive was wiped but I didn't. I thought the system would would still be able to do the install but it isn't able to connect with the apple server when it attempts to install the OS. I am trying to reinstall High Sierra which is the last OS that that model can run. I have another MAC but am unable to download the install package for High Sierra even through it's still available in the Apple store. It's not compatible with the system I was using to attempt to download the package so the button to get the download is greyed out. Does anyone out there know of a link to download the High Sierra OS without going through the apple store? I have downloaded the previous OS "Sierra" but don't have the instructions for creating a bootable install USB for that particular OS.