Software Update Missing

priscilla_kerdock wrote:

When i try to download it it says "This copy of the Install macOS Mojave application is damaged, and can‘t be used to install macOS."

Did you use Safari, or some other browser?

Try using Safari on How to get old versions of macOS - Apple Support, going down to the version of macOS your system is compatible with.

Try installing this 10.4.6 Mojave in Safe Mode, but not using Firefox...

https://itunes.apple.com/us/app/macos-mojave/id1398502828?mt=12

Safe Boot, (holding Shift key down at startup).

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.