How to fix Error 880 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: Error 880 – Resilient Buffer Pool Extension Version Mismatch

Why This Error Happens

This error occurs when SQL Server 2025’s resilient Buffer Pool Extension (BPE) feature detects that the persisted state file on disk was written by a different binary version than the one currently starting up. This commonly happens after an in-place upgrade, a cumulative update installation, or a rollback where the SQL Server binaries changed but the old BPE cache file was left on disk. Because the persisted buffer pool extension format is version-locked for data integrity reasons, SQL Server refuses to load a mismatched file rather than risk silent data corruption.

Step-by-Step Resolution Guide

Step 1: Identify the Persisted BPE File Location

  • Open SQL Server Configuration Manager or check the SQL Server error log for the BPE file path (typically a .bpe file in a path like D:\SQLData\BufferPoolExtension\).
  • Confirm the SQL Server version by running SELECT @@VERSION; in a working instance or checking setup.exe /Version from the installation media.
  • Cross-reference the build number in the error log against the currently installed binary version in Help > About or via sqlservr.exe -v.

Step 2: Remove or Relocate the Incompatible BPE File

  • Stop the SQL Server service using net stop MSSQLSERVER (or the appropriate named instance service).
  • Navigate to the BPE file path and rename or move the .bpe file to a backup location (e.g., C:\Temp\BPE_Backup\).
  • Ensure no other process has a lock on the file using Resource Monitor or handle.exe from Sysinternals.

Step 3: Reconfigure the Buffer Pool Extension

  • Restart the SQL Server service: net start MSSQLSERVER.
  • Re-enable BPE using T-SQL:
ALTER SERVER CONFIGURATION
SET BUFFER POOL EXTENSION ON
(FILENAME = 'D:\SQLData\BufferPoolExtension\BPE.bpe', SIZE = 8 GB);
  • Confirm the SQL Server service account has Modify permissions on the target BPE directory in Windows 11/Server 2025 File Explorer security settings.

Step 4: Validate Binary Consistency Across the Cluster (If Applicable)

  • For Always On Availability Groups or Failover Cluster Instances, verify all nodes are running the identical SQL Server 2025 build using SELECT SERVERPROPERTY('ProductVersion'); on each node.
  • Apply any pending Cumulative Updates uniformly across all nodes before re-enabling BPE.

Alternative or Verification Steps

  • Check the SQL Server Error Log (ERRORLOG file, usually in C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\LOG\) for a confirmation message indicating “Buffer Pool Extension is enabled” with no version warnings on the next startup.
  • If the error persists, disable BPE entirely with ALTER SERVER CONFIGURATION SET BUFFER POOL EXTENSION OFF;, then re-run Step 3 to rebuild the extension file from scratch rather than reusing any legacy file.