> db.survey.find() { "_id" : 1, "results" : [ { "item" : "A" , "score" : 5, "answers" : [ "a1" , "a2" , "a3" ] }, { "item" : "B" , "score" : 8, "answers" : [ "a2" , "a3" , "a4" ] } ] } { "_id" : 2, "results" : [ { "item" : "C" , "score" : 8, "answers" : [ "a1" , "a2" ] }, { "item" : "B" , "score" : 4, "answers" : [ "a1" , "a2" ] } ] } > db.survey.update( {}, { $pullAll : { "results.answers" : [ "a3" , "a4" ]}}, { multi : true }) cannot use the part (results of results.answers) to traverse the element ({results: [ { item: "A" , score: 5.0, answers: [ "a1" , "a2" , "a3" ] }, { item: "B" , score: 8.0, answers: [ "a2" , "a3" , "a4" ] } ]}) WriteResult({ "nMatched" : 0, "nUpserted" : 0, "nModified" : 0, "writeError" : { "code" : 16837, "errmsg" : "cannot use the part (results of results.answers) to traverse the element ({results: [ { item: \" A\ ", score: 5.0, answers: [ \" a1\ ", \" a2\ ", \" a3\ " ] }, { item: \" B\ ", score: 8.0, answers: [ \" a2\ ", \" a3\ ", \" a4\ " ] } ]})" } })