Unable to install the downloaded version of TT2018 that my subscription provided. It generates an error saying cannot start the setup process. Any suggestions???

I've tried the link in the subscription email multiple times. I've manually downloaded the install file as well. All with the same result (cannot start the setup process). I've rebooted my system numerous times, I've used admin privileges - same result. I can successfully install any other install file on my computer including TT2017.

Any suggestions, please & thank you.