How to fix Error 2795 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 2795 – FILESTREAM Mismatch

Why This Error Happens

Error 2795 occurs when an operation (such as adding or altering a column, index, or partition) attempts to apply a new FILESTREAM filegroup or attribute that conflicts with the existing FILESTREAM configuration already defined on the table. This typically happens when a table was originally created with a specific FILESTREAM filegroup binding, and a subsequent DDL statement references a different filegroup name or omits a required FILESTREAM clause. It can also surface after a database restore or attach operation where the FILESTREAM filegroup mapping does not match the original schema definition stored in system metadata.

Step-by-Step Resolution Guide

Step 1: Identify the Current FILESTREAM Filegroup Binding

  • Run the following query to inspect existing filegroup assignments:
SELECT name, type_desc, is_default 
FROM sys.filegroups 
WHERE type = 'FD';
  • Cross-reference this with sys.tables and sys.data_spaces to confirm which FILESTREAM filegroup is currently bound to the affected table.
  • Note the exact filegroup name reported in the error message ('%.*ls') versus the one your script is trying to apply.

Step 2: Correct the DDL Statement to Match the Bound Filegroup

  • Open the script that triggered the error (e.g., ALTER TABLE, CREATE TABLE, or CREATE INDEX).
  • Update the FILESTREAM_ON clause to reference the correct, existing filegroup name, for example:
ALTER TABLE dbo.YourTable 
SET (FILESTREAM_ON = 'FS_FileGroup_Correct');
  • If you intended to move FILESTREAM data to a new filegroup, you must first create and add the new filegroup to the database before referencing it:
ALTER DATABASE YourDB 
ADD FILEGROUP FS_NewGroup CONTAINS FILESTREAM;

ALTER DATABASE YourDB 
ADD FILE (NAME = FS_NewGroup_File, FILENAME = 'C:\SQLData\FSData_New') 
TO FILEGROUP FS_NewGroup;

Step 3: Validate Metadata After Restore or Attach Operations

  • If the error appeared after a database restore/attach on Windows Server 2025, confirm the FILESTREAM directory paths exist and are accessible under the SQL Server service account.
  • Use sp_helpfile and sys.database_files to ensure the FILESTREAM file paths match the original source server structure.
  • If mismatched, either recreate the missing filegroup/path structure locally or modify the table definition to reference the filegroup now present in the restored database.

Alternative or Verification Steps

  • After applying the fix, re-run the original DDL statement and confirm it completes without Error 2795; verify by querying sys.filegroups and sys.tables to ensure the table’s FILESTREAM reference matches the intended filegroup.
  • If the issue persists, drop and recreate the FILESTREAM-enabled column/table in a test environment using a unified filegroup name from the start, then migrate data via INSERT INTO ... SELECT to avoid legacy metadata conflicts.