How to fix Error 673 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: Error 673 – Failure to Access Row Object in Snapshot Isolation

Why This Error Happens

Error 673 occurs when SQL Server encounters memory corruption or an inconsistency while attempting to access a row version in the version store under snapshot isolation. This is typically caused by faulty physical memory (RAM), a corrupted buffer pool page, or an unstable storage subsystem returning inconsistent data during row-versioning operations. In rarer cases, it can result from a bug or resource exhaustion in tempdb, where version store data is maintained.

Step-by-Step Resolution Guide

Step 1: Run Hardware and Memory Diagnostics

  • Open Windows Memory Diagnostic on Windows Server 2025 / Windows 11 by running mdsched.exe and selecting “Restart now and check for problems.”
  • Check the Windows Event Viewer under Windows Logs > System for WHEA-Logger errors, which indicate hardware-level memory or CPU faults.
  • If using a hypervisor (Hyper-V), verify host-level memory integrity and disable Dynamic Memory ballooning for the SQL Server VM temporarily.

Step 2: Validate Database and Tempdb Integrity

  • Run DBCC CHECKDB('YourDatabaseName') WITH NO_INFOMSGS, ALL_ERRORMSGS; to detect and repair any corruption in the affected database.
  • Execute DBCC CHECKDB('tempdb') since the version store for snapshot isolation resides in tempdb, and corruption there directly causes Error 673.
  • Review the SQL Server Error Log (C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\Log\ERRORLOG) for accompanying messages that reference specific page IDs or file corruption.

Step 3: Reconfigure Tempdb and Isolation Settings

  • Ensure tempdb has adequate space and multiple data files (one per logical CPU core, up to 8) to reduce contention and version store pressure.
  • Temporarily disable snapshot isolation on the affected database using: ALTER DATABASE YourDatabaseName SET ALLOW_SNAPSHOT_ISOLATION OFF;
  • Re-enable it after confirming stability: ALTER DATABASE YourDatabaseName SET ALLOW_SNAPSHOT_ISOLATION ON;

Step 4: Apply Latest SQL Server 2025 Cumulative Update

  • Navigate to the Microsoft Update Catalog and download the latest Cumulative Update (CU) for SQL Server 2025.
  • Install the update in a maintenance window, as CUs often contain fixes for row-versioning and buffer pool defects.
  • Restart the SQL Server service via SQL Server Configuration Manager after installation completes.

Alternative or Verification Steps

  • Re-run the workload or query that originally triggered Error 673 and monitor the SQL Server Error Log for recurrence over a 24–48 hour period.
  • If the error persists after hardware and integrity checks pass clean, restore the affected database from a known-good backup and re-test under snapshot isolation to rule out residual corruption.