# PyMongo: pymongo.errors.BulkWriteError: batch op errors occurred

**Code:** `pymongo.errors.BulkWriteError: batch op errors occurred` · **Category:** MongoDB · **Seen on:** MongoDB, Python

A bulk insert/update had one or more failed operations; details are in `e.details`.

## Meaning

Catch the exception and inspect `e.details['writeErrors']` for index, code and message (e.g. 11000 duplicate). Use `ordered=False` to continue after errors, and handle duplicates deliberately (`upsert`, `$setOnInsert`).

## Common causes

- Duplicate keys in `insert_many`
- Validation failures
- Unique index violations
- Writes exceeding size limits
- Permission errors

## Quick fix

1. `try: ... except BulkWriteError as e: print(e.details["writeErrors"])`
2. Use `ordered=False`
3. Replace inserts with upserts where appropriate

## Detailed fix by platform

### Python

1. `coll.insert_many(docs, ordered=False)  # continue past duplicates`

## How to diagnose

1. **details** — writeErrors?
2. **Code** — 11000?
3. **Ordered** — False?

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Source: [WhatIsMyError](https://whatismyerror.com/errors/mongodb/pymongo-bulkwriteerror)