Troubleshooting Guide: SQL Server Error 4865 — “Cannot Bulk Load Because the Maximum Number of Errors Was Exceeded”

Why This Error Happens

Error 4865 occurs when the BULK INSERT, BCP, or OPENROWSET(BULK...) operation encounters more malformed, mismatched, or improperly delimited rows than the value specified (or defaulted) in the MAXERRORS parameter. This is typically caused by incorrect field terminators, row terminators, data type mismatches between the source file and destination table schema, or a corrupted/truncated source data file. In many cases, the default MAXERRORS value of 10 is simply too low for large files with legacy encoding issues or inconsistent row formatting.

Step-by-Step Resolution Guide

Step 1: Identify the Exact Rows Causing Failures

• Re-run the bulk load operation with an ERRORFILE clause to capture bad rows without stopping the process immediately.
• Example syntax: BULK INSERT dbo.TargetTable FROM 'C:\Data\import.csv' WITH (ERRORFILE = 'C:\Data\import_errors.log', MAXERRORS = 50);
• Open the generated .log and .log.Error.Txt files to inspect which specific rows and columns triggered the rejection.

Step 2: Validate Source File Formatting and Schema Alignment

• Confirm the field terminator (e.g., comma, pipe) and row terminator (\n vs \r\n) in the source file match what is declared in your FORMAT file or WITH clause.
• Check for encoding mismatches — ensure the file is saved as UTF-8 or UTF-16 depending on what SQL Server 2025 expects, especially if the data contains extended Unicode characters.
• Compare column data types in the destination table against the raw text values; look for unexpected NULLs, extra delimiters, or unescaped quotation marks in text fields.
• If using a format file, regenerate it using bcp with the -f switch to ensure it reflects the current table schema:
• bcp dbo.TargetTable format nul -c -f C:\Data\TargetTable.fmt -S YourServerName -T

Step 3: Increase the MAXERRORS Threshold Temporarily for Diagnosis

• If the file is mostly valid but contains a known number of bad rows, raise the threshold to allow the batch to complete while still logging failures.
• Example: BULK INSERT dbo.TargetTable FROM 'C:\Data\import.csv' WITH (FORMATFILE = 'C:\Data\TargetTable.fmt', MAXERRORS = 1000, ERRORFILE = 'C:\Data\import_errors.log');
• Do not set this value arbitrarily high in production without reviewing the error log afterward — this is a diagnostic step, not a permanent fix.

Step 4: Clean or Pre-Process the Source Data File

• Use PowerShell or a staging script to strip out malformed rows, fix encoding, or normalize delimiters before re-attempting the import.
• Example PowerShell check for inconsistent column counts per row:
• Get-Content C:\Data\import.csv | ForEach-Object { ($_ -split ',').Count } | Sort-Object -Unique
• Re-import the cleaned file using a fresh BULK INSERT command with the corrected MAXERRORS value reset closer to default (e.g., 10–20).

Step 5: Check Permissions and File Accessibility on Windows Server 2025

• Ensure the SQL Server service account has NTFS read permissions on the folder containing the source file (right-click file → Properties → Security tab).
• Confirm the file path is accessible from the SQL Server instance itself, not just your local machine, especially if SQL Server runs under a different service account or in a containerized/clustered environment.

Alternative or Verification Steps

• After applying fixes, re-run the original BULK INSERT statement with MAXERRORS reset to a low number (e.g., 10) and confirm it completes without triggering Error 4865.
• If errors persist, consider importing the data via SQL Server Import and Export Wizard or SSIS, which provide more granular row-level error handling and visual mapping to catch schema mismatches before execution.