I am looking for the solution to downgrade my Mac as some of the Apps are not working in latest macOS. I can’t afford to lose my critical data while doing this. Can I get the support from expert to help me on this?
There are a couple of things you need to do before going back. First do a back up of your drive to an external drive. Second - you need to obtain a copy of the full installer of the OS you want to install. You do not have a choice of OS versions from the App Store.