MongoDB missing collection
WiredTiger connects collection metadata in the MongoDB catalog to ident files in dbPath. If a .wt file is missing, orphaned, renamed, or no longer matches the catalog, repair may prioritize starting the server over preserving every document.
Understand the symptom
Recovery maps collection UUIDs, idents, WiredTiger.wt, _mdb_catalog, checkpoints and journal history. A file known to one metadata source may be salvageable; a file missing from both metadata sources may not be automatically associated with its original collection.
What you may see
The catalog references a WiredTiger table whose .wt file is absent.
Repair created a stub so the database could start.
A collection file exists but is missing from one or both metadata catalogs.
WiredTiger metadata or a collection table cannot be opened normally.
Protect the source
Unsalvageable data may be renamed or replaced with an empty table.
Checkpoints, journal and catalog identity must match the same database state.
A repaired node should not rejoin until data changes and replica state are understood.
Do this now
Prevent restart loops, repair, compaction and replica resync.
Copy every WiredTiger file, journal, lock state, diagnostics, keys and configuration.
Save namespace, UUID, ident, server version, topology and exact startup errors.
Snapshot or image the underlying storage before salvage or file replacement.
NEPFOSYS process
NEPFOSYS correlates collection metadata, idents, files and checkpoints on the copy.
Candidate files, backups, replica members and journals are evaluated without altering production.
Recovered BSON, indexes and priority collections are checked in an isolated environment.
A clear next step
Start a case with the exact symptoms, incident timeline, prior attempts, encryption details, and the files that matter most. NEPFOSYS will route the case to the appropriate DFW intake or nationwide mail-in path.
Start with a case reviewQuestions, answered
It may create an empty stub so the server starts, which does not recover the missing documents.
Sometimes, when enough catalog or WiredTiger metadata remains to identify and salvage it.
Not directly into production without confirming checkpoint, catalog and replica consistency.
DFW local · Nationwide mail-in