Yosemite upgrade
I am trying to upgrade from Yosemite and can't, even though all the requirements are met on my mid 2010 iMac 27". What am I doing wrong?
What happens when you try? Error message(s)? Have you tried the installation in another admin user account or the Safe Mode?
Your computer should be able to run High Sierra.
Check to make sure your applications are compatible.
macOS Sierra 10.12: Compatible Apps
Also check to make sure there is a compatible driver for your printer.
Do a backup before installing, preferable 2 backups on 2 different drives.