Valhalla DSP is a small, independent developer. There are many "cracked" links online that contain malware. To get the official, safe, and fully functional VST3 link:
Download the Mac installer from the Valhalla DSP Demos & Downloads Page. vst plugin valhallaroom vst3 link
Here is a cheat sheet for the 8 algorithms included in your : Valhalla Room VST3: A Comprehensive Review of the