macOS Mojave 10.14 download is damaged? Cannot download

Delete "Install macOS Mojave" from the Applications folder. Download again while in Safe Mode.

How to use safe mode on your Mac - Apple Support

Choose Applications from the Finder's Go menu, throw the installer away, and download another copy.

(192013)

Same thing here. I have a mid-2012 MacBook Pro and Mojave is as far up the OS chain as it can go; currently running High Sierra. The AppStore Mojave installer downloads but instead of launching, up pops a message that this copy of the installer is damaged and cannot be used to install the OS.

Thanks, dialabrain, that is exactly what fixed the situation.

You're welcome.