How to fix Error 5339 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 5339 — CSV Format Restriction with BCP Data File Type

Why This Error Happens

Error 5339 occurs when the bcp utility or BULK INSERT command is executed with the FORMAT = 'CSV' option alongside an incompatible datafiletype value, such as native or widenative. SQL Server 2025 strictly enforces that the CSV format option is only valid when paired with char or widechar datafiletype arguments. This restriction exists because CSV formatting relies on character-based field and row terminators, which cannot be interpreted correctly against binary or native data representations.

Step-by-Step Resolution Guide

Step 1: Review the BCP Command Syntax

  • Open the command prompt or PowerShell session where the bcp command was issued.
  • Check the -c (char) or -w (widechar) flag is present; CSV format requires one of these.
  • Example of an invalid command: bcp dbo.Table out data.csv -n -t, -r\n -S server -T
  • Note that -n specifies native type, which is incompatible with CSV formatting.

Step 2: Correct the Datafiletype Argument

  • Replace -n (native) or -N (widenative) with -c (char) or -w (widechar) in your bcp command.
  • Corrected example: bcp dbo.Table out data.csv -c -t, -r\n -S server -T
  • If using BULK INSERT in T-SQL, verify the DATAFILETYPE parameter is set to 'char' or 'widechar' in the WITH clause.
  • Example: BULK INSERT dbo.Table FROM 'C:\Data\import.csv' WITH (FORMAT='CSV', DATAFILETYPE='char', FIRSTROW=2);

Step 3: Validate Format File Compatibility (If Used)

  • Navigate to the format file location, typically under C:\SQLData\FormatFiles\.
  • Open the .fmt or .xml format file in a text editor and confirm field types are set to SQLCHAR rather than binary types like SQLBINARY or SQLNUMERIC.
  • Regenerate the format file if necessary using: bcp dbo.Table format nul -c -x -f C:\SQLData\FormatFiles\table.xml -S server -T

Step 4: Re-run the Import/Export Operation

  • Execute the corrected bcp or BULK INSERT command.
  • Confirm the operation completes without raising Error 5339 in the SQL Server Error Log or command output.

Alternative or Verification Steps

  • Verify success by checking SQL Server Logs (C:\Program Files\Microsoft SQL Server\MSSQL17.MSSQLSERVER\MSSQL\Log\ERRORLOG) for absence of Error 5339 entries after re-running the command.
  • If CSV output is not strictly required, consider using -n (native format) for faster, binary-safe data transfer between SQL Server instances instead of forcing CSV compatibility.