Disabled Index

This warning has been raised because a disabled index has been found. Either enable the index if it was disabled unintentionally or drop the index.

To rebuild and enable a disabled index, use the ALTER INDEX REBUILD statement or the CREATE INDEX WITH DROP_EXISTING statement.

Suggested Action

The index isn't currently being used, therefore dropping will not alter how the instance is behaving.

How to Re-Enable an Index in SQL Server

ALTER INDEX IX_Name ON TableName REBUILD;
GO  

How to Drop an Index in SQL Server

DROP INDEX IX_Name ON TableName;
GO  

Further Reading

Disable Indexes and Constraints | Microsoft Docs

Enable Indexes and Constraints | Microsoft Docs

DROP INDEX (Transact-SQL) | Microsoft Docs