How to fix Error 5277 on Windows Server 2025 / Windows 11

by

Troubleshooting Guide: SQL Server Error 5277 – Database Snapshot Split Point LSN Mismatch

Why This Error Happens

Error 5277 occurs when SQL Server’s internal database snapshot mechanism detects that the split point Log Sequence Number (LSN) does not align correctly with the first LSN recorded in the sparse file chain. This typically happens due to corruption in the sparse file used for the database snapshot, an unexpected shutdown during a snapshot-based operation (such as DBCC CHECKDB or a snapshot-based backup), or underlying storage-level inconsistencies on Windows Server 2025 that prevent proper synchronization of the snapshot’s transaction log metadata. In rare cases, this can also surface when antivirus or filesystem-level filters interfere with sparse file I/O on NTFS/ReFS volumes.

Step-by-Step Resolution Guide

Step 1: Identify and Remove the Corrupted Database Snapshot

  • Run SELECT name, source_database_id FROM sys.databases WHERE source_database_id IS NOT NULL; to list active snapshots.
  • Drop the affected snapshot using DROP DATABASE [YourSnapshotName];
  • Confirm no automated jobs (e.g., DBCC CHECKDB internal snapshots) are still referencing the sparse file in C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\DATA\.

Step 2: Validate Storage and Filesystem Integrity

  • Open Event Viewer (eventvwr.msc) and check the System log for disk-related Event IDs (51, 153) around the same timestamp as Error 5277.
  • Run chkdsk C: /f /r (adjust drive letter to your data volume) during a maintenance window to repair NTFS/ReFS inconsistencies.
  • Temporarily disable third-party antivirus real-time scanning on the SQL data directory to rule out file-locking interference with sparse files.

Step 3: Recreate the Snapshot and Re-run the Originating Operation

  • Manually create a fresh snapshot using CREATE DATABASE YourSnapshotName ON (NAME = YourDB, FILENAME = 'C:\SQLData\YourSnapshot.ss') AS SNAPSHOT OF YourDB;
  • Re-execute the operation that triggered the error, such as DBCC CHECKDB('YourDB') WITH NO_INFOMSGS, ALL_ERRORMSGS;
  • Monitor the SQL Server Error Log (SSMS > Management > SQL Server Logs) for recurrence of Event ID 5277.

Step 4: Restore from a Known Good Backup (If Corruption Persists)

  • If the snapshot mechanism continues to fail, restore the source database from the last verified full backup using RESTORE DATABASE YourDB FROM DISK = 'D:\Backups\YourDB.bak' WITH RECOVERY;
  • Apply any subsequent transaction log backups in sequence to minimize data loss.
  • Validate database consistency post-restore with DBCC CHECKDB before resuming production workloads.

Alternative or Verification Steps

  • Verify resolution by running DBCC CHECKDB with no errors returned and confirming the SQL Server Error Log shows no further 5277 entries over a 24-hour monitoring period.
  • If the issue persists despite storage repairs, open a Microsoft support case referencing Event ID 5277 and attach the SQLDIAG output along with the Windows Server 2025 System/Application event logs for deeper analysis of potential storage driver or filesystem filter conflicts.