## TL;DR
Fix this in Labelbox by acting on the exact message first: open the export at the reported line, join any label value that contains a literal newline, and re-export with one JSON object per physical line. Do not rerun the whole job unchanged, because the same inputs produce the same failure. Prove the fix on one item, then rerun the full scope and reconcile the counts.

```text
NDJSON parse error at line 142
```

## Use this when
- The operation in Labelbox fails with this exact message: NDJSON parse error at line 142.
- The same failure repeats on retry with unchanged inputs.
- A review, export or check is blocked until this item completes.

## Not for this skill when
- The message is a permission or outage notice from the platform. Resolve that first, then return here if this error remains.
- The operation completes and you only disagree with its output. That is a quality review, not this failure.

## Steps
1. Reproduce the failure with the smallest scope that still shows it in Labelbox, and copy the full message plus the item, user or metric involved into the run notes. Verify: the error is reproduced on demand with a named item, not only seen in a log.
2. Apply the specific fix for this error: open the export at the reported line, join any label value that contains a literal newline, and re-export with one JSON object per physical line. Verify: parse every line independently and count parsed rows against the data row count.
3. Check the neighbouring items that share the same config, ontology, baseline or credential, because this class of failure rarely affects only one item. Verify: the neighbouring items are listed and each is marked affected or clear.
4. Compare the result counts, decisions or alerts against the source in Labelbox so a silent partial success is caught before sign off. Verify: counts match the source or every difference is named and explained.
5. Rerun the original operation in Labelbox on the previously failing scope, watching for the same message rather than assuming success from a quiet log. Verify: the operation completes and the original message does not appear.
6. Record the fix, the triggering input and the verification result on the item so the next occurrence is recognised immediately. Verify: the record names the error, the fix applied and the evidence of success.

## Why it happens
NDJSON requires one complete JSON object per line; a multiline string inside a label breaks the line framing and every parser after that line fails.

## Variant phrasings

### NDJSON parse error at line 142
The verbatim form searchers paste from the terminal or console. Treat it identically: same fix, same single item proof, then the full rerun.

### How to fix: Labelbox export failed error "NDJSON parse error at line 142"
The how-to phrasing for the same failure in Labelbox. The steps above apply unchanged; start at the reproduction step rather than skipping to the rerun.

### Labelbox troubleshooting for this failure
The symptom-first phrasing used when the console hides the full message. Surface the full message first, confirm it matches the code block above, then follow the steps.

Compatibility: Labelbox at current versions, plus the platform API or console the query names; no extra tooling beyond a text editor and the source system access needed to verify counts.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_oXUQXsAQE5Ppu9jhTfZbWg