How to fix Error 4875 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 4875 – Invalid Column Attribute from BCP Client

Why This Error Happens

Error 4875 occurs when the bcp utility or a BULK INSERT operation sends column metadata that does not match the structure expected by SQL Server 2025 for the target table. This typically happens due to a mismatched or corrupted format file (.fmt), an outdated bcp client version communicating with a newer server version, or a schema change (such as a dropped or reordered column) that was not reflected in the format file. In rarer cases, this can also stem from a corrupted data file where column delimiters or attribute flags are malformed.

Step-by-Step Resolution Guide

Step 1: Validate the Format File Against the Target Table Schema

  • Open the .fmt file used in your bcp command (e.g., C:\BCP\orders.fmt) in a text editor.
  • Confirm the number of columns listed matches the current column count in the destination table using sp_help TableName in SSMS.
  • Check that data types, column order, and collation entries align exactly with the table definition — a mismatch here is the most common trigger for Error 4875.

Step 2: Regenerate the Format File

  • Delete the old or suspect format file to avoid using stale metadata.
  • Run the following command from an elevated Command Prompt to regenerate a fresh native format file:
  bcp YourDatabase.dbo.YourTable format nul -c -f C:\BCP\YourTable.fmt -S YourServerName -T
  • Re-run your original bcp import/export command using this newly generated format file.

Step 3: Verify Client and Server Version Compatibility

  • Confirm the bcp.exe version matches a build compatible with SQL Server 2025 by running bcp -v in Command Prompt.
  • If running an older bcp utility (e.g., from SQL Server 2019 tools), download and install the latest Microsoft Command Line Utilities from the Microsoft Download Center.
  • On Windows Server 2025 / Windows 11, ensure the SQL Server Native Client or ODBC Driver 18+ is installed, as legacy drivers can misreport column attributes.

Step 4: Inspect the Source Data File for Corruption

  • Open the source .dat or .csv file in a text editor and check for unexpected delimiters, encoding issues (e.g., UTF-8 vs. UTF-16 mismatch), or truncated rows near the column referenced in the error (colid %d).
  • Re-export the source data cleanly if corruption or encoding mismatches are found.

Alternative or Verification Steps

  • Run a small test import using only 5–10 rows of sample data with the regenerated format file to confirm the column mapping succeeds before processing the full dataset.
  • If the error persists, bypass the format file entirely by using the -c (character mode) switch with a simple comma-delimited structure, letting bcp auto-detect column attributes instead of relying on a manually defined file.