What causes "The file contains invalid syntax" in RocketChat/Rocket.Chat?

Open the failing entryName from the log and validate it: plain UTF-8, comma-delimited, every field properly quoted

The file contains invalid syntax

Error message

The file contains invalid syntax

What it means

The CSV importer parses each messages.csv entry from the uploaded zip; the CSV parser threw on this file, meaning its syntax does not match the expected dialect. The file is skipped — its messages are lost from the import — while the progress counter still advances so the import completes.

Source

Thrown at apps/meteor/server/lib/import/csv/CsvImporter.ts:171

				increaseProgressCount();
				continue;
			}

			// Parse the messages
			if (entry.entryName.indexOf('/') > -1) {
				if (this.progress.step !== ProgressStep.PREPARING_MESSAGES) {
					await super.updateProgress(ProgressStep.PREPARING_MESSAGES);
				}

				const item = entry.entryName.split('/'); // random/messages.csv
				const folderName = item[0]; // random

				let msgs = [];

				try {
					msgs = this.csvParser(entry.getData().toString());
				} catch (e) {
					this.logger.warn({ msg: 'The file contains invalid syntax', entryName: entry.entryName, err: e });
					increaseProgressCount();
					continue;
				}

				let data: { username: string; ts: string; text: string; otherUsername?: string; isDirect?: true }[];
				const msgGroupData = item[1].split('.')[0]; // messages
				let isDirect = false;

				if (folderName.toLowerCase() === 'directmessages') {
					isDirect = true;
					data = msgs.map((m) => ({
						username: m[0],
						ts: m[2],
						text: m[3],
						otherUsername: m[1],
						isDirect: true,
					}));
				} else {

View on GitHub (pinned to b2c16d5842)

Solutions

Open the failing entryName from the log and validate it: plain UTF-8, comma-delimited, every field properly quoted
Re-export ensuring each row is username,timestamp,text with quotes around any field containing commas or newlines
Re-zip with the expected folder structure and re-run the import

Defensive patterns

Strategy: validation

Validate before calling

// validate the CSV before feeding the parser
import { parse } from 'csv-parse/sync';

function parseMessagesCsv(raw: string): unknown[] {
	return parse(raw, { delimiter: ',', relax_quotes: false, skip_empty_lines: true, bom: true });
}

Try / catch

try {
	msgs = this.csvParser(entry.getData().toString());
} catch (e) {
	this.logger.warn({ msg: 'The file contains invalid syntax', entryName: entry.entryName, err: e });
	increaseProgressCount();
	continue; // skip file, keep the import going
}

Prevention

Validate every messages.csv with a CSV linter before zipping the import file
Export with UTF-8, comma delimiter, and quoted fields containing commas/newlines
Keep the expected folder structure inside the zip unchanged

When it happens

Trigger: Delimiter mismatch (file uses ';' but the parser expects ','), unbalanced/missing quotes around fields containing commas, stray newlines inside unquoted message text, files saved by Excel with BOM/UTF-16 encoding, or a non-CSV file placed at the expected path inside the zip.

Common situations: Hand-edited CSV exports; Excel 'Save as CSV' with regional settings producing different delimiters or encodings; zips built with wrong folder layout on Windows; message text containing raw line breaks.

Related errors

AI-assisted analysis of RocketChat/Rocket.Chat@b2c16d5842 (2026-08-18). Data as JSON: /api/errors/88341f03004b3632. Report an issue: GitHub.