Atlas error: $vectorSearch index not found

TL;DR: The query names an index that does not exist, is the wrong type, or is still building. Check getSearchIndexes before touching the query. Confirm Run db.[collection].getSearchIndexes(). Check three things: 1.

The error

index not found

The fix

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

When to use this

• You are seeing this exact error message; match the block above, not just part of it.
• The failing call matches the scenario in the title: Atlas error.
• You want the fastest verified fix before digging through logs.

When not to use this

• Your error text differs from the block above; close cousins often have different causes.
• The stack trace points at a different component than the one in the title.
• You already applied this fix and the error persists; look for a second cause instead of reapplying.

Compatibility

• Not pinned to a specific version; follows current Atlas behavior.

Also seen as

• FAILED

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.