Above. Install progress is as follows: Branded dialog, then engine splash screens; then ESO dialog (“Exit”/“Continue” buttons); user license agreement; install location selected (/Volumes/ExtStorage/Applications/ESO); counted up to 94%, then dialog closed and “Launcher is damaged and can’t be opened. You should move it to the trash.”

Thanks.

Thanks, ZOS_Bill for responding. The issue appears to be a permissions issue and not a launcher issue (although technically it's a permissions issue as relates to the launcher running from the target drive/resource I'm trying to install it to). Attempting to replace the Launcher as requested in the referenced KB article had zero effect. If you could provide some indication of permissions I need to set on the target folder (I'll create it beforehand) and which user/users need what permissions to that hierarchy I'd appreciate it. I'm also assuming that the installer will set child permissions of the folders/links it creates in the process, but if not, I'd like to have that information as well.

An installation to the default boot volume appears to be working (downloading files now, which was much further than I got before), but as I mentioned in my initial message, I don't want to run it from the boot volume because of the sheer volume of space it requires (160G plus; this is one-third my total storage on the boot volume and I need that space for photo/video processing). Please advise.

Thanks.

Both "eso" and "Launcher" need access to your user documents folder(where the "Elder Scrolls Online" folder should stay), in you "Privacy and security/Files and folders" preferences.
And giving "Accessibility" granted to the "eso" is a plus, which has often solved the problems of "crazy" mice.
Hope it help :-)