How to fix Error 1997 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 1997 – XML/Spatial Index Conversion Failure

Why This Error Happens

This error occurs when you attempt to use CREATE INDEX ... WITH (DROP_EXISTING = ON) to modify an existing XML or spatial index while changing its type to a standard relational (B-tree) index. SQL Server 2025 does not allow the DROP_EXISTING clause to change the fundamental index type in a single operation because the underlying storage structures for XML/spatial indexes are architecturally incompatible with relational index pages. The engine blocks this to prevent metadata corruption, requiring an explicit drop-and-recreate sequence instead.

Step-by-Step Resolution Guide

Step 1: Identify the Conflicting Index

  • Open SQL Server Management Studio (SSMS) 21 or Azure Data Studio connected to your Windows Server 2025 instance.
  • Run the following query to confirm the index type causing the conflict:
SELECT name, type_desc FROM sys.indexes WHERE object_id = OBJECT_ID('YourTableName');
  • Look for type_desc values of XML or SPATIAL matching the index name in the error message.

Step 2: Manually Drop the Existing Index

  • Since DROP_EXISTING cannot convert the index type, you must remove it manually first.
  • Execute the explicit drop command:
DROP INDEX [YourIndexName] ON [dbo].[YourTableName];
  • Verify there are no dependent constraints or foreign keys relying on this specific index before dropping.

Step 3: Create the New Relational Index

  • Once the old XML/spatial index is removed, create the new relational index using the exact same name.
  • Use a standard CREATE INDEX statement without the DROP_EXISTING option, as the index no longer exists:
CREATE INDEX [YourIndexName] ON [dbo].[YourTableName] (ColumnName);
  • If working in a high-availability environment (Always On), ensure this change is synced to replicas via the primary node.

Step 4: Validate Application Dependencies

  • Check any stored procedures or ORM mappings (Entity Framework, Dapper) that might reference the index via hints (WITH (INDEX(YourIndexName))).
  • Update deployment scripts (DACPAC/SSDT) to reflect a “Drop and Create” step rather than an “Alter” step for this specific index moving forward.

Alternative or Verification Steps

  • Verification: Run sys.dm_db_index_physical_stats or check the Index Properties in SSMS Object Explorer to confirm the type_desc now reads NONCLUSTERED instead of XML or SPATIAL.
  • Alternative: If the index is tied to a replication schema or deployment pipeline, use a pre-deployment script in SSDT to explicitly DROP the index before the main schema update runs, bypassing the DROP_EXISTING logic entirely.