How to fix Error 1789 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: Error 1789 — “Cannot use CHECKSUM(*) in a computed column”

Why This Error Happens

This error occurs because SQL Server 2025 explicitly disallows the CHECKSUM(*) function when it is used as part of a computed column definition, since the wildcard * requires evaluation against all columns in the row — including ones that may be added or dropped later — which conflicts with the static, pre-defined nature of a computed column’s expression. The engine cannot guarantee a stable, deterministic schema binding for CHECKSUM(*) because the column list it references is dynamic rather than fixed at creation time. This is a T-SQL syntax/design limitation rather than a permissions, port, or file corruption issue, so it will occur consistently regardless of server configuration.

Step-by-Step Resolution Guide

Step 1: Identify the Offending Computed Column Definition

  • Locate the CREATE TABLE or ALTER TABLE statement that defines the computed column.
  • Search specifically for a pattern like: ALTER TABLE dbo.YourTable ADD RowCheck AS CHECKSUM(*);
  • Confirm via SQL Server Management Studio (SSMS) Object Explorer under Tables > Columns that the column is marked as “Computed.”

Step 2: Replace CHECKSUM(*) with an Explicit Column List

  • Rewrite the computed column expression to reference specific, named columns instead of the wildcard.
  • Example fix:
  ALTER TABLE dbo.YourTable
  ADD RowCheck AS CHECKSUM(Column1, Column2, Column3);
  • This ensures the expression is deterministic and schema-bound correctly, since SQL Server can validate the exact column list at object-creation time.

Step 3: Drop and Recreate the Column (If Already Partially Created)

  • If the table was left in an inconsistent state from a failed script, drop the broken computed column first:
  ALTER TABLE dbo.YourTable DROP COLUMN RowCheck;
  • Re-run the corrected ALTER TABLE ... ADD statement from Step 2.
  • Refresh the table metadata in SSMS (right-click database > Refresh) to confirm the column now appears without error flags.

Step 4: Validate Downstream Dependencies

  • Check any stored procedures, views, or triggers that reference CHECKSUM(*) directly in queries (not just computed columns), as these may also need updating for consistency.
  • Use sp_depends or the Dependencies viewer in SSMS to find all objects referencing the affected table.

Alternative or Verification Steps

  • Verify the fix by querying the column directly: SELECT RowCheck FROM dbo.YourTable; — it should return values without throwing Error 1789.
  • As an alternative to CHECKSUM, consider using HASHBYTES('SHA2_256', CONCAT(Column1, Column2, Column3)) for a more collision-resistant row-hashing approach in the computed column.