How to fix Error 5138 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 5138

Why This Error Happens

This error occurs when SQL Server 2025 attempts to create, rename, or reference a database file on cloud storage (such as Azure Blob Storage or an S3-compatible endpoint) using a file name that contains one or more trailing space characters. Cloud storage APIs typically normalize or strip trailing whitespace from object keys, which creates a mismatch between the name SQL Server expects and the name actually stored by the cloud provider. This validation was introduced specifically for cloud-backed file streams because local NTFS volumes tolerate trailing spaces in file names, but remote object storage does not guarantee consistent round-trip behavior for them.

Step-by-Step Resolution Guide

Step 1: Identify the Offending File Name

  • Check the full error message text for the exact file name referenced in the ‘%.*ls’ placeholder.
  • Run the following query to inspect current database file names and look for unintended trailing characters:
  SELECT name, physical_name, LEN(name) AS name_len, LEN(RTRIM(name)) AS trimmed_len
  FROM sys.master_files;
  • Compare name_len and trimmed_len — a mismatch confirms a trailing space is present.

Step 2: Correct the File Name in the T-SQL Script or Application Code

  • Open the script, ETL job, ORM mapping, or application config that generated the CREATE DATABASE, ALTER DATABASE, or BACKUP/RESTORE statement.
  • Remove any trailing whitespace from the logical or physical file name string, especially in concatenated variables (e.g., @FileName + ' ').
  • Use TRIM() or RTRIM() explicitly when building dynamic SQL file paths:
  SET @FileName = RTRIM(@FileName);
  • Re-run the operation using the corrected name against the cloud storage container (Azure Blob, S3, etc.).

Step 3: Validate Cloud Storage Credential and Endpoint Configuration

  • Confirm the CREATE CREDENTIAL or DATABASE SCOPED CREDENTIAL object used for cloud storage access does not itself contain a padded secret or URL with trailing spaces.
  • Check sys.external_data_sources (if using PolyBase/External Tables) or the BACKUP URL syntax for extra spaces copy-pasted from documentation or spreadsheets.
  • On Windows Server 2025, verify any automation (PowerShell scripts, scheduled tasks, or SQL Agent jobs) that builds file name strings isn’t appending a space via string formatting, such as "$fileName " in PowerShell.

Step 4: Re-test the Operation

  • Execute the original CREATE DATABASE ... ON (NAME = ..., FILENAME = 'https://<account>.blob.core.windows.net/container/file.mdf') command with the cleaned file name.
  • Confirm the operation completes without raising Error 5138.

Alternative or Verification Steps

  • Re-run DBCC CHECKDB or query sys.master_files / sys.database_files again to confirm all file names report equal LEN() and LEN(RTRIM()) values, indicating no trailing spaces remain.
  • If the error persists despite a clean name, test the same file name against the cloud storage container directly (e.g., using Azure Storage Explorer or AWS CLI ls) to rule out a provider-side naming restriction or hidden Unicode whitespace character (such as a non-breaking space) that RTRIM() alone may not remove — in that case use TRANSLATE() or REPLACE() to strip the specific character code.