How to fix Error 5255 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 5255 – Sort Page Movement Failure

Why This Error Happens

Error 5255 occurs when SQL Server’s internal page-allocation engine attempts to relocate a page that is currently flagged as part of an active sort operation, typically during index rebuilds, DBCC operations, or shrink/defrag processes. This condition is usually triggered by database corruption, an interrupted sort workspace in tempdb, or a concurrent maintenance operation (such as a shrink running simultaneously with an index rebuild) that conflicts over page ownership. In most cases, the underlying cause is either disk-level corruption or insufficient tempdb space causing improper sort page management.

Step-by-Step Resolution Guide

Step 1: Verify Database and Tempdb Integrity

  • Run DBCC CHECKDB ('YourDatabaseName') WITH NO_INFOMSGS, ALL_ERRORMSGS; to identify corruption.
  • Check tempdb health separately using DBCC CHECKDB (tempdb); since sort operations rely heavily on tempdb workspace.
  • Review the SQL Server error log (via C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\Log\ERRORLOG) for related I/O or allocation warnings preceding Event ID 5255.

Step 2: Halt Conflicting Maintenance Operations

  • Confirm no concurrent DBCC SHRINKDATABASE, DBCC SHRINKFILE, or index reorganize/rebuild jobs are running against the same database simultaneously.
  • Query sys.dm_exec_requests to identify any active sessions performing sort-dependent operations.
  • Terminate or reschedule overlapping jobs via SQL Server Agent (Object Explorer > SQL Server Agent > Jobs).

Step 3: Resize and Validate Tempdb Configuration

  • Navigate to SQL Server Management Studio (SSMS) > Server Properties > Database Settings and confirm tempdb data/log file growth settings are not set to restrictive fixed sizes.
  • Increase tempdb initial size using: ALTER DATABASE tempdb MODIFY FILE (NAME = tempdev, SIZE = 8192MB);
  • Ensure tempdb files are placed on a dedicated, low-latency SSD volume (e.g., E:\TempDB\) separate from OS and user database drives.

Step 4: Rebuild Affected Indexes Offline

  • Identify the affected object using the page ID reported in the error (Page %d:%d) via DBCC PAGE (with trace flag 3604 enabled) to map it to a table/index.
  • Rebuild the specific index offline to avoid concurrent sort conflicts: ALTER INDEX [IndexName] ON [TableName] REBUILD WITH (ONLINE = OFF, SORT_IN_TEMPDB = ON);
  • Monitor Windows Event Viewer (Applications and Services Logs > MSSQLSERVER) for recurrence during the rebuild.

Step 5: Apply Latest Cumulative Update

  • Confirm your SQL Server 2025 build number via SELECT @@VERSION; and compare against the latest Cumulative Update (CU) from Microsoft’s release notes.
  • Download and install the newest CU package, as sort-page handling bugs in allocation logic are frequently addressed in servicing updates.
  • Restart the SQL Server service through Services.msc (Windows Server 2025) after installation.

Alternative or Verification Steps

  • Re-run DBCC CHECKDB and the previously failing maintenance operation (index rebuild/shrink) to confirm Error 5255 no longer appears in the SQL Server logs or Windows Event Viewer.
  • If the error persists, restore the affected database from a known-good backup to a test instance and compare index/page structures to isolate whether the corruption is storage-hardware related (check Windows Server 2025 Disk Management and run chkdsk on the underlying volume).