This is a known issue, and here's why: 


When companies create executables, they usually "sign" the builds, to tell the AntiVirus that it's a "safe" file.
As the betas are created at a fairly high volume, sometimes you get what's called an unsigned build - which means the build can set off your AV.
Just verify and install - there's nothing but the renderer in there and maybe a Material Library if you did the full install.