How to fix Error 448 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: Error 448 – Invalid Collation ‘%.*ls’ in SQL Server 2025

Why This Error Happens

This error occurs when SQL Server encounters a collation name in a COLLATE clause, database creation script, or column definition that it does not recognize as valid. This is typically caused by a typo in the collation name, a reference to a legacy or deprecated collation not supported in SQL Server 2025, or a mismatch when restoring/migrating a database from a different server that used a custom or platform-specific collation. It can also occur if the Windows Server 2025 locale settings do not have the corresponding language pack installed, making Windows-based collations unavailable to the SQL Server instance.

Step-by-Step Resolution Guide

Step 1: Verify the Exact Collation Name

  • Run the following query to list all valid collations supported by your SQL Server 2025 instance:
  • SELECT name FROM sys.fn_helpcollations();
  • Compare the collation string from your script/error message against this list character-by-character, checking for extra spaces, incorrect casing, or missing underscores.

Step 2: Check for Deprecated or Renamed Collations

  • Cross-reference the collation name against Microsoft’s official “Collation and Unicode support” documentation for SQL Server 2025, as some legacy SQL collations (e.g., older SQL_ prefixed ones) have been phased out.
  • If migrating from an older instance (SQL Server 2012 or earlier), replace deprecated collations with their modern Windows equivalent (e.g., replace SQL_Latin1_General_CP1_CI_AS with Latin1_General_100_CI_AS_SC_UTF8 if Unicode support is required).

Step 3: Validate Windows Server Locale and Language Pack Support

  • Open Settings > Time & Language > Language & Region on Windows Server 2025 / Windows 11 and confirm the required language pack is installed if using a region-specific collation.
  • Restart the SQL Server service via services.msc or run net stop MSSQLSERVER && net start MSSQLSERVER after installing any missing language packs so SQL Server reloads the updated system locale data.

Step 4: Correct the Script or Connection String

  • Locate the exact line in your T-SQL script, SSIS package, or application connection string invoking the invalid collation.
  • Update the COLLATE clause with the corrected, verified collation name from Step 1, for example:
  • ALTER TABLE dbo.YourTable ALTER COLUMN YourColumn NVARCHAR(50) COLLATE Latin1_General_100_CI_AS_SC_UTF8;

Alternative or Verification Steps

  • Re-run the original script or database restore operation; if Error 448 no longer appears, the collation reference is now valid.
  • As an alternative, if you’re unsure of the correct value, remove the explicit COLLATE clause entirely to let the column/database inherit the server or database default collation instead.