The MUX plug-in packages here below contain the MUX demo version.
This demo version regularly inserts a soft noise into the audio output.
Upon purchasing a MUX UL Vst User License, you'll receive your personal user key.
You do not need to reinstall the MUX plug-in, just insert your user key to activate MUX UL and the demo noise will be gone.
Download the MUX package, unzip it to a new folder and move that folder into your favorite VST plug-in folder. Then eventually let your VST host do a rescan so it finds this new plug-in.