can i downgrade high sierra to sierra?

I too want to downgrade to Sierra from High Sierra.
I have a Time Machine backup but it only goes back to June 2017. I can't find a Sierra download package in it, so I guess I must have deleted it some time earlier, not thinking I'd ever need it again.

It doesn't show in my App Store account, either - though El Capitaine, Mountain Lion and Lion do.

How can I get a Sierra download, so I can re-install it?

Or is there another way of doing this?

I too would like some help in order to downgrade to Sierra. I followed excellent instructions elsewhere and successfully produced a bootable version of Sierra. However, right at the end of the download I had a message to say that the version of Sierra I had downloaded was corrupt and would not run. I therefore trashed it and downloaded another. However, when I went into Terminal to start the process again, I received an error message. Here is the full script:

Last login: Sun Dec 24 17:36:39 on ttys000

iMac:~ johnwallace$ sudo /Applications/Install\ macOS\ Sierra.app/Contents/ Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Users/johnwallace/Desktop/Downgarde\ to\ Sierra/Install\ macOS\ Sierra.app

Password:

sudo: /Applications/Install macOS Sierra.app/Contents/: command not found

iMac:~ johnwallace$

I have googled 'command not found' and understand that the path has been corrupted and that I need to put another command into Terminal to correct it. Can anyone tell me what that command should be?

Many thanks!

Well, following on from the above, I downloaded Diskmaker X and tried both an HDD and a thumb drive and in both cases I received the error message 'Could not unmount disk'. So I thought that the Terminal command line was probably corrupted so i reinstalled High Sierra. I then tried Diskmaker X again and got the same error message. Then I tried using the command in terminal and got the same message 'Command not found'. There doesn't seem to be any way for me to install Sierra other than completely wiping my HD. Any ideas?

Connecting to the Mac App Store

You may need to create a USB installer.

Yes, by restoring from a Time Machine backup created prior to upgrading macOS.

Sorry. Perhaps I can just restore the whole system from Time Machine. Is that so?

If so, what else do I need to restore?

I also have problems with High Sierra - very squirrelly.

But, what do I lose if I go back to Sierra? It also wasn't the best OS, but much better than High Sierra.

I found Mavericks to be the most stable and fastest but going back to Sierra from High Sierra will not cost much in features. Photos was the biggest user change in High Sierra.