What causes "e (no own message; error opening CSV file)" in pentaho/pentaho-kettle?

Inspect the 'cause' of the KettleException in the stack trace to identify the underlying IOException or VFS error.

pentaho/pentaho-kettle · error · KettleException

e (no own message; error opening CSV file)

Error message

e (no own message; error opening CSV file)

What it means

openNextFile wraps its work (VFS lookup, file opening, NIO channel setup, BOM detection) in a try/catch. KettleExceptions are rethrown unchanged, but any other Exception (IOException from FileObject resolution, file disappearance, permission errors, etc.) is wrapped in a new KettleException with no added message, so the original cause is preserved only as the cause chain.

Solutions

Inspect the 'cause' of the KettleException in the stack trace to identify the underlying IOException or VFS error.
Verify the file exists and is readable at the configured path before/while the transformation runs.
Check VFS connection settings (credentials, host, scheme) if the filename is a remote URL.
Re-run the transformation; if it is a transient race with file deletion, regenerate the file list just before reading.

Defensive patterns

Strategy: try-catch

Validate before calling

// pre-flight check before running the transformation
if (!java.nio.file.Files.isReadable(java.nio.file.Paths.get(filename))) {
  throw new IllegalStateException("File missing or unreadable: " + filename);
}

Try / catch

try { ... } catch (KettleException e) {
  Throwable cause = e.getCause();
  logError("Failed opening CSV file: " + (cause != null ? cause.toString() : e.getMessage()), e);
  setErrors(1);
}

Prevention

Always read the cause chain — the wrapper carries no message
Regenerate file lists immediately before reading to avoid races
Verify VFS credentials/scheme for non-local URLs
Ensure files are not deleted between listing and reading

When it happens

Trigger: Any non-Kettle exception during openNextFile: VFS cannot resolve the filename, the file was deleted between listing and opening, wrong credentials for a VFS provider, or an I/O error while opening the file channel.

Common situations: Race condition where a file listed by a previous step no longer exists; malformed file URL; OS-level permission problems; VFS provider misconfiguration (e.g. bad SFTP credentials).

Understand the failure class

Background: "open() failed", "failed to open file", "cannot create file" — what a file open error means and how to fix it — this error's family across 42 libraries.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/5e2075f0f22f4292. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/trans/steps/csvinput/CsvInput.java:418

          logBasic( BaseMessages.getString( PKG, "CsvInput.Log.HeaderRowSkipped", data.filenames[ data.filenr - 1 ] ) );
          if ( data.fieldsMapping.size() == 0 ) {
            return false;
          }
        }
      }
      // Reset the row number pointer...
      //
      data.rowNumber = 1L;

      // Don't skip again in the next file...
      //
      data.bytesToSkipInFirstFile = -1L;

      return true;
    } catch ( KettleException e ) {
      throw e;
    } catch ( Exception e ) {
      throw new KettleException( e );
    }
  }

  protected int getBOMSize( String vfsFilename ) throws Exception {
    int bomSize = 0;
    try ( FileInputStream fis = new FileInputStream( vfsFilename );
          BufferedInputStream bis = new BufferedInputStream( fis ) ) {
      BOMDetector bom = new BOMDetector( bis );

      if ( bom.bomExist() ) {
        bomSize = bom.getBomSize();
      }
    }

    return bomSize;
  }

  FieldsMapping createFieldMapping( String fileName, CsvInputMeta csvInputMeta )

View on GitHub (pinned to f3058517a1)