2016-01-26T21:45:15.675+0000 E REPL     [repl writer worker 5] writer worker caught exception:  :: caused by :: 16836 The _id field cannot be changed from {_id: null} to {_id: ObjectId('56a7e8ec19637e8640000001')}. on: { ts: Timestamp 1453844715000|94, h: -6008654494445131386, v: 2, op: "i", ns: "xxxxx.xxxxxx_users", o: { _id: null, _type: "SuperAdmin", email: "xxxx+xxxx@xxx.xx", password_digest: "$2a$10$44l7q88l1FW8E4FiHR61CeGdAmV/uBAQiV3emGY9RgXZmW1WENDKe", updated_at: new Date(1453844715921), created_at: new Date(1453844715921), _id: ObjectId('56a7e8ec19637e8640000001') } }
2016-01-26T21:45:15.675+0000 I -        [repl writer worker 5] Fatal Assertion 16360
2016-01-26T21:45:15.678+0000 I -        [repl writer worker 5]