Can't install latest update

Hey guy’s i am trying to re-install Horizon… i downloaded the latest update and when i click on it it says the software is corrupted. I’m trying to use it for the achievement unlocker.
any tips?

Thanks

Uninstall Horizon if you currently have it installed, and reinstall after downloading the latest version from this link: https://www.horizonmb.com/client/v2/latest.php