Everytime I attempt to download macOS High Sierra or Mojave my computer tells me the version is "damaged". How do I fix this?

The error message is not very informative, what it really means is that the App Store has

detected a copy of the Install macOS High Sierra.app and Install macOS Mojave.app in

your Applications folder. Locate it/ them and move it/ them to your Applications folder,

move it/ them to the Trash and empty the Trash.

Connect your mac to your router via cable, Restart your mac and go back to the

App Store High Sierra / Mojave downloads page. The App Store should now say Get or

Download rather than Open.

Do not use the mac while it its downloading or any other devices that share the same internet

connection.

Don't use FireFox for this link…

https://itunes.apple.com/app/macos-high-sierra/id1246284741?mt=12

If you get a corrupted message...

Naw, 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 High Sierra App in Applications, so expired Certificates are not expired.

Or... trash the Install MacsOS High Sierra.app in Applications then a new copy more recent version can be downloaded.

If you get a corrupted message...

Naw, not damaged, it's just that you have an old copy already in Applications.

Trash the Install MacsOS *******.app in Applications then a new copy more recent version can be downloaded.

If you get a corrupted message...

Naw, 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 Mohave App in Applications, so expired Certificates are not expired.

Or... trash the Install MacsOS Mojave.app in Applications then a new copy can be downloaded.