Due to performance and other issues I want to re-install Sierra on a older mac mini currently running High Sierra.
I have the Install MacOS Sierra.app file.
When I attempt the installation I get the following message:
"This Copy of the Install MacOS application is too old to be opened in this version of MacOS"
Does anyone know of a workaround?
Thank you.
iMac, OS X Mountain Lion (10.8.5)
You can Restore from a Time Machine backup if you keep one:
How to use Time Machine to back up or restore your Mac - Apple Support
If not, you'd need to erase your disk and then download Sierra from the AppStore. It's a bit of work.
But as Allan says, before you do that you may want to find out what the problem is in High Sierra. Running Etrecheck is a good start.
Before doing that if you can please run an EtreCheck report and post the results here maybe we can suggest hoot fix your Mac rather the doing the downgrade of the operating system.
I suggest you use the program created by Etresoft, a frequent contributor. It will provide a snapshot of your system which we can analyze to possibly determine the cause of your problem. Please use copy and paste as screen shots can be hard to read. On the screen with Options, please open Options and check the bottom 2 boxes before running. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown.
install macos sierra
