How to fix Error 10526 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: Error 10526 — Cannot Drop Trigger Referenced by Plan Guide

Why This Error Happens

This error occurs because SQL Server 2025 prevents the deletion of a DML/DDL trigger when an active plan guide has been explicitly bound to it for query optimization purposes. The Database Engine maintains a dependency link between the plan guide and the trigger object to ensure the specified execution plan (hints) remains valid and enforceable. Since dropping the trigger would orphan the plan guide and break the query optimization strategy, the engine blocks the DROP TRIGGER operation until the dependency is manually removed.

Step-by-Step Resolution Guide

Step 1: Identify the Conflicting Plan Guide

  • Open SQL Server Management Studio (SSMS) and connect to the target instance running on Windows Server 2025 or Windows 11.
  • Run the following query to locate the specific plan guide name referencing the trigger:
SELECT name, scope_type, scope_type_desc, is_disabled 
FROM sys.plan_guides 
WHERE scope_type_desc = 'OBJECT';
  • Cross-reference the scope_object_id column with OBJECT_ID('YourTriggerName') to confirm the exact match mentioned in the error message.

Step 2: Record the Plan Guide Definition

  • Before deleting anything, back up the logic by querying the full definition:
SELECT name, hints, query_text 
FROM sys.plan_guides 
WHERE name = 'PlanGuideNameFromStep1';
  • Copy the hints and query_text output into a .sql script file and save it to a local directory (e.g., C:\SQLBackups\PlanGuides\) for future re-creation if needed.

Step 3: Drop the Plan Guide

  • Execute the sp_control_plan_guide system stored procedure to remove the dependency using the DROP parameter:
EXEC sp_control_plan_guide N'DROP', N'PlanGuideNameFromStep1';
  • Confirm the command returns a success status with no error messages in the “Messages” tab of SSMS.

Step 4: Execute the Original Drop Command

  • Retry the original command that triggered Error 10526:
DROP TRIGGER YourTriggerName;
  • Verify the command completes without being blocked by the previous dependency check.

Step 5: Recreate the Plan Guide (Optional)

  • If the trigger logic is being updated rather than permanently removed, recreate the trigger first.
  • Use the sp_create_plan_guide procedure with the parameters saved in Step 2 to reapply the optimization hints to the new object.

Alternative or Verification Steps

  • Verification: Run SELECT * FROM sys.plan_guides; again after the fix to ensure the specific plan guide entry no longer appears in the result set and that the trigger ID is removed from sys.triggers.
  • Alternative: If sp_control_plan_guide fails due to permissions, ensure the executing login has ALTER ANY DATABASE DDL TRIGGER or CONTROL permission on the database, as plan guide manipulation requires elevated schema-modification rights in SQL Server 2025.