Mongodb error code 11000 – How we fix it

Application and web sites create also a lot information even in a single transaction.

How can we manage this enormous quantity of information effectively?

Thanks to the NoSQL capabilities of MongoDB, it tends to make web sites scalable and provides superior overall performance.

Nevertheless, the MongoDB error code 11000 can occur due to duplicate entries or poor syntax.

At Bobcares, we usually get requests from our clients to repair MongoDB error code 11000 as component of our Server Migration Solutions.

Now, let’s see how our Migration Engineers repair MongoDB error code 11000.


How we fixed MongoDB error code 11000

At Bobcares, exactly where we have extra than a decade of knowledge in managing servers, we see a lot of clients face complications whilst managing MongoDB database.

Now let’s see the important causes for MongoDB errors and how our Assistance Engineers repair the top rated errors.


1. Incorrect syntax

Lately, a single of our customers wanted to recover information from a MySQL database and transform it into JSON for integration into the MongoDB database.

When it was a single insertion it worked fine. But whilst undertaking 45000 insertion, it did not function and resulted in the error:

(node:31032) UnhandledPromiseRejectionWarning: WriteError({"code":11000,"index":0,"errmsg":"E11000 duplicate key error collection: meteor.depart index: _id_ dup key: { : ObjectId('5b1527ee6161057938e0aef0') }","op":{"jourExpl

On checking our MongoDB Specialists located that the difficulty occurred due to syntax error.

When applying insertMany, we ought to use the forceServerObjectId flag. As a result, we recommended the client to use the following code to resolve the difficulty.

manyInsert.insertMany(dataJsonInsert, { forceServerObjectId: correct }) 

This fixed the difficulty.


2. Duplicate record

Similarly, a different client had an  E11000 duplicate essential error index in MongoDB mongoose. The error stated

Error generating new user: WriteError({"code":11000,"index":0,"errmsg":"insertDocument :: triggered by :: 11000 E11000 duplicate essential error index

On checking the schema, we located that the client renamed the field to username, but didn’t take away the old index. By default, MongoDB will set the worth of a non-existent field to null in that case.

If a document does not have a worth for the indexed field in a distinctive index, the index for this document will retailer a null worth.

Due to the distinctive situation, MongoDB will only enable a single document lacking the indexed field. Also, If there is extra than a single document with no a worth for the indexed field or is missing the indexed field, the index execution will fail and benefits in a duplicate essential error.

So, our Assistance Engineers removed the index for the renamed name field and solved the error.


[Need assistance to fix MongoDB error code 11000? We’;ll help you.]



In brief, the MongoDB error code 11000 may perhaps occur when a document does not have a worth for the indexed field or due to the incorrect syntax applied. Today, we saw the several causes for MongoDB errors and how our Assistance Engineers repair them.

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