Trying to install v11.16.3beta

Check antivirus logs, or disable real-time scanning in case it is terminating the process, perhaps. (Some antivirus will treat new exe files as suspicious until they get enough reports of the same file to consider it 'common'.)

Some of the suggestions under Problems installing Opus may also help. The error message isn't the same as any of the cases, but once or twice we've seen the same fixes work for other error messages.