This warning has been raised because the index is hypothetical. This means that the index is maintained by SQL Server, but is never used for queries.
Hypothetical indexes are generated by the Index Tuning Wizard and Database Tuning Advisor. Although they should be deleted once the tools have finished, there may be cases when an error has caused the application to crash and the index to remain. Unless either of the tools are were in use during the Aireforge scan, hypothetical indexes should be dropped, as they serve no benefit.
💡 Aireforge Advisor can automatically generate a script for this.
Drop the hypothetical index.
How to Drop a Hypothetical Index in SQL Server
DROP INDEX IX_Name ON TableName; GO
sys.indexes (Transact-SQL) | Microsoft Docs