Registry modifications
Generally standard users only contain write access to locations under HKEY_CURRENT_USER. When UAC is On, both standard user accounts and users that are members of the Administrators group will fail. When UAC is Off, only members of the Administrators group will succeed.
U s ing " H igh e s t ava il a bl e "
Using the "Highest available" setting means that your AutoPlay application is designed to be run by all users. The application runs with the same access token as the parent process. This means that if the application is run by a member of the Administrators group, their privileges will be elevated to the Administrator's full access token when given their consent. However, this also means that if a standard user ran the application, they would only have their highest privileges, those being a standard user. Therefore all issues mentioned above for "As invoker" would exist using this setting resulting in
possible application failure. Again, if your application performs administrator tasks, the "Require administrator" option should be used in addition to the usual administrator detection and conditions.
U s ing " Re qui re a d m ini s t ra t o r "
Using the "Require administrator" setting means that your AutoPlay application performs tasks that can only be achieved by a member of the Administrators group running with full privileges.