I'm trying to download High Sierra. I'm following the steps here: https://support.apple.com/en-us/HT208969
but when I clink on the link in step 4: https://itunes.apple.com/us/app/macos-high-sierra/id1246284741?ls=1&mt=12
it gives an error in iTunes: "Item Not Available, The item you've requested is not currently available in the U.S. store."
Since your mac can get further than HighSierra you can not use the os that is downloaded from the appstore.
You should download it here:
https://itunes.apple.com/us/app/macos-high-sierra/id1246284741?ls=1&mt=12
I tried, from Safari. It takes me to a High Sierra download on the App Store but when I click to download I get a message that the link "is damaged and cannot be used to install" and btw I also get the same message if I try to do it with Mojave. I can't install Catalina on this MacBook Pro, but I can no longer sync my updated iPhone with Sierra. But I seem to be prevented from installing the OSX's between the two.
These links to Apple special sites do not work in Firefox !
Go yo your Applications folder and find "Install Mac OS High Sierra" delete the installer. Then restart your Mac and try again with Safari.
The link for High Sierra doesn't work
