This warning has been raised because SQL Server's statistics indicate that this index has never been used.
NOTE: This warning is purely based on SQL Server's statistics, which are only populated by querying of the database. If the database has just been restarted or restored, or it's a replica database that is never used for selects, then the statistics will not accurately represent whether the index is used or not.
Consider dropping the index.
Any suggestion from Aireforge should be thoroughly tested before being implemented into production.