Multifactor authentication on older Macs
These Macs are the oldest Macs that will run Sierra, with their Machine ID (the x,y numbering after the date below) in the system profiler:
- MacBook (Late 2009 or newer) 6,1
- MacBook Pro (Mid 2010 or newer) 6,1
- MacBook Air (Late 2010 or newer) 3,1
- Mac mini (Mid 2010 or newer) 4,1
- iMac (Late 2009 or newer) 10,1
- Mac Pro (Mid 2010 or newer) 5,1
Sierra needs to be upgraded to 10.12.4 or later via one of these updates, after backing up of data:
10.12.4 Delta (to 10.12.3) or Combo 10.12.4 (for any earlier release of 10.12)
10.12.6 Combo with 2019-005 Security Update Sierra
dependinng on compatibility, once at 10.12.4, full multifactor authentication is supported on AppleID, iTunes, Mac App Store, and iCloud.
High Sierra upgrading is also a possibility for many Sierra compatible Macs, as long as software and drivers are compatible.
For those that can't upgrade to 10.12 at all, when you receive a login code on any device already registered with the AppleID, insert the code following the password trying to login the AppleID on the computer running the older MacOS to complete logging in AppleID.
Some may want newer iTunes release, but will need to upgrade further, as is indicated on this tip:
iTunes/Mac OS/iOS compatibility - Apple Community