How to fix Error 4526 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 4526 — Isolation Level Table Hint Conflict with Snapshot Materialized Views

Why This Error Happens

This error occurs because SQL Server 2025 applies transaction isolation level table hints (such as READUNCOMMITTED, SERIALIZABLE, or REPEATABLE READ) directly to query objects, but it cannot safely reconcile these hints with a view that relies on snapshot materialization without first “expanding” that view into its underlying base table logic. Snapshot-materialized views cache a consistent point-in-time dataset, and overriding isolation behavior at the view level creates ambiguity about which consistency model should govern the read. SQL Server blocks the query outright rather than risk returning inconsistent or stale data, requiring the EXPAND VIEWS query hint to explicitly tell the optimizer to substitute the view definition with its base tables before applying the isolation hint.

Step-by-Step Resolution Guide

Step 1: Identify the Offending Query and View

  • Locate the exact query referenced in the error message, including the view name shown in the %.*ls placeholder.
  • Run sp_helptext 'ViewName' in SSMS or Azure Data Studio to confirm the view uses snapshot materialization (check for WITH (MATERIALIZED_SNAPSHOT = ON) or similar syntax in SQL Server 2025’s extended view options).
  • Check the query execution plan or client application logs to find where the isolation level table hint (e.g., WITH (READUNCOMMITTED)) is being applied against the view.

Step 2: Add the EXPAND VIEWS Query Hint

  • Modify the query to include the OPTION (EXPAND VIEWS) hint at the end of the statement.
  • Example syntax:
  SELECT * FROM dbo.SalesSnapshotView WITH (READCOMMITTED)
  OPTION (EXPAND VIEWS);
  • If the query originates from an ORM (Entity Framework, Dapper, etc.) or a stored procedure, update the underlying T-SQL definition rather than the application code directly.
  • Save and redeploy the stored procedure using SSMS or a deployment pipeline (e.g., sqlpackage.exe for DACPAC updates).

Step 3: Update Stored Procedures and Application Code

  • Search your codebase and SQL Server object definitions for all instances referencing the affected view with isolation hints.
  • Use the following query to find dependent objects:
  SELECT referencing_schema_name, referencing_entity_name
  FROM sys.dm_sql_referencing_entities('dbo.ViewName', 'OBJECT');
  • Apply the OPTION (EXPAND VIEWS) hint consistently across all identified queries and recompile affected stored procedures using EXEC sp_recompile 'ProcedureName'.

Step 4: Restart the SQL Server Service (If Plan Caching Persists the Error)

  • Open Services.msc on Windows Server 2025 or Windows 11.
  • Locate SQL Server (MSSQLSERVER) or the named instance service.
  • Right-click and select Restart to clear any cached execution plans that may still reference the invalid hint combination.
  • Alternatively, run DBCC FREEPROCCACHE; in SSMS to clear the plan cache without a full service restart.

Alternative or Verification Steps

  • Verify the fix by re-running the original query in SSMS and confirming Error 4526 no longer appears; check sys.dm_exec_query_stats to confirm the query plan now reflects an expanded view execution.
  • If the error persists, consider removing the isolation level table hint entirely and instead setting the session-level isolation using SET TRANSACTION ISOLATION LEVEL before the query, which avoids the view-expansion requirement altogether.