I was getting this error a lot last night, I thought it was because I was trying the 'Move Deployment' in Vortex to manage mod installs, but then changed back to the Hardlink Deployment method midway through setting up my profile because I was getting fed up with Vortex throwing that window up to Apply/Undo changes to Mods outside of Vortex each time I added a mod, and thought this is what had now broke and was causing that UAC error. Could not work out what was going on as I have full access and control over the Fallout folder and Vortex folders for any and all users on my Gaming PC, I even had Vortex running as Administrator to make sure. Then after several minutes I began to pay attention more to the message and noticed it was the same Mod/File everytime. So I deleted the mod and went back to the page and downloaded it fresh. Installed it and this time no error. Guess the mod got screwed up in the download and deleting it and trying again fixed it. I then attributed this to the issue I'm having where Vortex can't or messes up downloads if I'm not using my VPN Connection.
same It says "Vortex needs to access "C:\Program Files (x86)\ The Elder Scrolls V Skyrim\data\sound" but doesn't have permission to. If your account has admin right Vortex can try to unlock the file for you."
It might help if you purchase the game legally. That is not an install path that a legal (i.e. non-pirated) copy can have, as they all go through Steam.