How to fix Error 682 on Windows Server 2025 / Windows 11

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Why This Error Happens

Error 682 typically occurs when the internal buffer allocated for reading a column’s data is smaller than the actual data being retrieved, often due to metadata corruption in the system catalog or page-level corruption within the data file. This mismatch can result from a torn page write, a hardware-level disk fault, or improper truncation of variable-length column definitions. In rarer cases, it stems from a SQL Server engine bug related to in-memory OLTP or columnstore index buffer estimation during query execution.

Step-by-Step Resolution Guide

Step 1: Run Immediate Consistency Checks

  • Open SQL Server Management Studio (SSMS) or use sqlcmd to connect to the affected instance.
  • Execute DBCC CHECKDB('YourDatabaseName') WITH NO_INFOMSGS, ALL_ERRORMSGS; to identify the exact page and object causing the buffer mismatch.
  • Review the output for allocation errors, specifically looking for “Msg 8928” or “Msg 8944” which often accompany Error 682.

Step 2: Isolate and Repair the Corrupted Object

  • If DBCC CHECKDB identifies a specific table, attempt to isolate the corruption using DBCC CHECKTABLE('SchemaName.TableName') WITH ALL_ERRORMSGS;.
  • If corruption is confirmed and isolated to non-clustered indexes, drop and rebuild the specific index using ALTER INDEX ALL ON TableName REBUILD; rather than a full repair.
  • Avoid using REPAIR_ALLOW_DATA_LOSS until all other recovery options (such as restoring from a clean backup) have been exhausted.

Step 3: Update SQL Server Cumulative Updates

  • Navigate to the Microsoft Update Catalog and check the current build version of SQL Server 2025 via SELECT @@VERSION;.
  • Apply the latest Cumulative Update (CU) for SQL Server 2025, as this error is frequently patched in updates addressing memory grant miscalculations for wide tables.
  • Restart the SQL Server service via services.msc on Windows Server 2025 to ensure the patch binaries are loaded correctly.

Step 4: Verify Windows Storage and Disk Health

  • Check the Windows Event Viewer under Windows Logs > System for any Disk or NTFS warnings correlating with the timestamp of the SQL error.
  • Run chkdsk C: /f /r (replacing C: with your data drive letter) during a scheduled maintenance window to rule out underlying physical disk corruption affecting the .mdf or .ndf files.

Alternative or Verification Steps

  • Verification: Re-run DBCC CHECKDB('YourDatabaseName') WITH NO_INFOMSGS; after the repair; a clean pass with zero allocation errors confirms the buffer/column mismatch has been resolved.
  • Alternative Fix: If corruption persists in system tables, restore the specific database from the last known good backup using RESTORE DATABASE... WITH RECOVERY, as this is safer than forcing a repair on system-level metadata.