Why is Q Prime installation stalling?

Trying to install Quartus Prime on a Windows 10 laptop. Downloaded install files directly because Akamai downloader failed. I have to get an admin to grant installation permission. When I start the Setup exe file (run as administator), it takes several minutes for the admin permission pop-up (Avecto). After IT guy puts in password, granting permission, no installer windows occur, even after waiting overnight! And yet, the installer is taking up 30+% of CPU. What's interfering with the installation?

Cheers!

MADman