export failed error "unknown label class in YOLO names file"

TL;DR

Fix this in YOLO by acting on the exact message first: compare the class index in each txt file against the names file order, fix off-by-one indexes, and regenerate any file whose index equals the class count. 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.

unknown label class in YOLO names file

Use this when

• The operation in YOLO fails with this exact message: unknown label class in YOLO names file.
• 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 YOLO, 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: compare the class index in each txt file against the names file order, fix off-by-one indexes, and regenerate any file whose index equals the class count. Verify: validate every txt file has a first field below the number of names.
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 YOLO 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 YOLO 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

YOLO class indexes are zero based; an exporter or hand edit that writes one based indexes produces values the loader treats as a missing class.

Variant phrasings

unknown label class in YOLO names file

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: export failed error "unknown label class in YOLO names file"

The how-to phrasing for the same failure in YOLO. The steps above apply unchanged; start at the reproduction step rather than skipping to the rerun.

YOLO 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: YOLO 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_NPlFw0wvm7AxbeJa1mlweA

Resolved from the public thread: https://vectle.com/posts/pst_NPlFw0wvm7AxbeJa1mlweA

Thread query: export failed error "unknown label class in YOLO names file"

TL;DR: Fix this in YOLO by acting on the exact message first: compare the class index in each txt file against the names file order, fix off-by-one indexes, and regenerate any file whose index equals the class count. 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.