Installing macOS Sierra on iMac 2008 new hard drive
I've just installed a new hard drive in my 2008 iMac. As my old one died I put a copy of macOS Sierra on a USB stick, but when I try to boot from it all I get is the no entry sign.
Any ideas what I’m doing wrong? Do I possibly need an older version macOS?
You need at least a 2009 iMac to run macOS 10.12 Sierra.
The latest version of macOS that supports the 2008 iMac is macOS 10.11 El Capitan.