How to fix Error 3226 on Windows Server 2025 / Windows 11

by

Troubleshooting Guide: SQL Server Error 3226 — “Failed to create snapshot for file”

Why This Error Happens

Error 3226 typically occurs during a database snapshot or backup operation when SQL Server cannot create the sparse file required for the snapshot process. This is most commonly caused by insufficient NTFS permissions on the target directory, the destination volume not supporting sparse files (such as ReFS misconfigurations or non-NTFS file systems), or insufficient disk space on the volume hosting the snapshot file. It can also occur if the SQL Server service account lacks the necessary rights to write to the specified path.

Step-by-Step Resolution Guide

Step 1: Verify File System Compatibility and Disk Space

  • Confirm the target volume is formatted as NTFS, since sparse files (required for snapshots) are not supported on FAT32 and have limited support on some ReFS configurations.
  • Run fsutil fsinfo volumeinfo C: (replace C: with your target drive) and check the “Supports Sparse Files” attribute.
  • Check available free space using File Explorer or Get-PSDrive in PowerShell to ensure the volume isn’t near capacity.

Step 2: Validate SQL Server Service Account Permissions

  • Open Services.msc and identify the account running the SQL Server (MSSQLSERVER) service.
  • Navigate to the target snapshot directory (e.g., D:\SQLData\Snapshots\), right-click → Properties → Security tab.
  • Ensure the SQL Server service account has Full Control or at minimum Modify, Read, and Write permissions on the folder.
  • If missing, click Edit → Add, enter the service account name, and apply the appropriate permissions.

Step 3: Check for File Path and Naming Conflicts

  • Ensure the snapshot file path specified in your CREATE DATABASE ... AS SNAPSHOT OF command does not already exist or conflict with a locked file.
  • Use sp_helpfile on the source database to confirm the number of files and ensure your snapshot script includes a matching NAME and FILENAME entry for every data file.
  • Avoid using mapped network drives (e.g., Z:\) in the FILENAME clause; use a local UNC or absolute path instead.

Step 4: Restart the SQL Server Service and Clear Locks

  • Restart the SQL Server service via SQL Server Configuration Manager to release any stale file handles.
  • Run the following command to check for blocking sessions on the source database:
  SELECT * FROM sys.dm_exec_requests WHERE database_id = DB_ID('YourDatabaseName');
  • Kill any blocking sessions using KILL <session_id> if they are preventing snapshot creation.

Step 5: Re-run the Snapshot Creation Command

  • Execute the CREATE DATABASE snapshot command again with verbose error reporting enabled.
  • Monitor the SQL Server Error Log (via SSMS → Management → SQL Server Logs) for any secondary error codes that provide additional context.

Alternative or Verification Steps

  • Verify the fix: Successfully run CREATE DATABASE YourDB_Snapshot ON (NAME = YourDB, FILENAME = 'D:\SQLData\Snapshots\YourDB.ss') AS SNAPSHOT OF YourDB; and confirm the snapshot appears under Databases → Database Snapshots in SSMS without error.
  • Alternative solution: If the issue persists on the same volume, redirect the snapshot file to a different NTFS-formatted drive with confirmed sparse file support and sufficient free space, then retest the operation.