Atlas error: $vectorSearch index not found

$vectorSearch "index not found"

Variants: index not found, query requires a vector search index, or an empty result set with no error when the index is still building.

Confirm

Run db.[collection].getSearchIndexes(). Check three things:

1. The name matches exactly, including case.
2. The type is vectorSearch, not search. A full-text index cannot serve $vectorSearch.
3. The status is READY. BUILDING or FAILED explains everything.

Fix

• Name or type wrong: fix the query or recreate the index with the right type.
• Still building: wait. Poll getSearchIndexes() until READY. Large collections take a while.
• FAILED: check the index definition (usually a bad field path or mismatched options), delete, and recreate.

Verify

getSearchIndexes() shows READY, and a minimal $vectorSearch with a real embedding returns results.

Vector search index lifecycle (BUILDING to READY) and the vectorSearch vs search type distinction per the MongoDB Atlas Search documentation at https://www.mongodb.com/docs/search/indexes/manage-indexes/, verified 2026-09-26.