Error
Error Code:
26
MongoDB Error 26: Namespace Not Found
Description
Error 26, 'Namespace Not Found', indicates that the database, collection, or index you are attempting to access does not exist within the MongoDB instance. This typically occurs during read, write, or administrative operations when the specified resource cannot be located.
Error Message
Namespace Not Found
Known Causes
4 known causesIncorrect Resource Name
The database, collection, or index name specified in the operation contains a typo or does not match the actual name.
Resource Does Not Exist
The target database, collection, or index has not been created yet or was previously dropped from the MongoDB instance.
Case Sensitivity Mismatch
MongoDB collection and database names are case-sensitive. The name used in the operation does not match the actual casing of the resource.
Wrong Database Context
The operation is being executed against an incorrect or unintended database, causing the desired namespace to be 'not found' in the current context.
Solutions
4 solutions available1. Verify Collection Name easy
Check collection exists with correct name
1
List all collections
show collections
// or
db.getCollectionNames()2
Check for typos
// Collection names are case-sensitive
db.Users.find() // Different from db.users.find()2. Create Collection easy
Collection is created automatically on first insert
1
Insert creates collection automatically
db.newcollection.insertOne({ name: "test" })2
Or create explicitly
db.createCollection("newcollection")3. Check Database easy
Collection might be in different database
1
Check current database
db.getName()2
Switch database
use correctdatabase
show collections4. Restore Dropped Collection medium
Recover from backup if accidentally dropped
1
Restore from mongodump
mongorestore --db mydb --collection users dump/mydb/users.bson