Helo Lisa,
macOS High Sierra - Technical Specifications
General Requirements
- OS X 10.8 or later
- 2GB of memory
- 14.3GB of available storage to perform upgrade*
- Some features require an Apple ID; terms apply.
- Some features require a compatible Internet service provider; fees may apply.
Mac Hardware Requirements
For details about your Mac model, click the Apple icon at the top left of your screen, choose About This Mac. These Mac models are compatible with macOS High Sierra:
- MacBook (Late 2009 or newer)
- MacBook Pro (Mid 2010 or newer)
- MacBook Air (Late 2010 or newer)
- Mac mini (Mid 2010 or newer)
- iMac (Late 2009 or newer)
- Mac Pro (Mid 2010 or newer)
- Don't use FireFox for these links…
https://support.apple.com/kb/sp765?locale=en_US
https://itunes.apple.com/app/macos-high-sierra/id1246284741?mt=12
macOS Mojave 10.14.6 - Technical Specifications
General Requirements
OS X 10.8 or later
2GB of memory
12.5GB of available storage (OS X El Capitan 10.11.5 or later)*
Some features require an Apple ID; terms apply.
Some features require a compatible Internet service provider; fees may apply.
Mac Hardware Requirements
For details about your Mac model, click the Apple icon at the top left of your screen and choose About This Mac. These Mac models are compatible with macOS Mojave:
MacBook (Early 2015 or newer)
MacBook Air (Mid 2012 or newer)
MacBook Pro (Mid 2012 or newer)
Mac mini (Late 2012 or newer)
iMac (Late 2012 or newer)
iMac Pro (2017)
Mac Pro (Late 2013; Mid 2010 and Mid 2012 models with recommended Metal-capable graphics cards)
Don't use FireFox for these links…
https://itunes.apple.com/us/app/macos-mojave/id1398502828?mt=12
If you get a corrupted message...
Naw, it's not damaged, it's just that you have an old copy already in Applications, there are 2 cures...
Disconnect from the Internet & set the Date back to 2014, then you can run the Install MacsOS ******* App in Applications, so expired Certificates are not expired.
Trash the Install MacsOS *******.app in Applications then a new copy more recent version can be downloaded.