First insert a document into an index db.test.createIndex({a: 1}) db.test.insert({_id: 1, a: "x"}) Find out the ident of the secondary index db.runCommand({aggregate: "test", cursor: {}, pipeline:[{$listCatalog: {}}]}) Shutdown the server. Dump the index table using a command similar to ~/mongo/build/install/bin/wt -r -C "log=(compressor=snappy,path=journal)" -h /data/db/ dump -x table:index-2-4842695354225906245 > error Open the file and modify the value of the keystring to 3c7800040002. Then load the data back to the table using a command similar to build/install/bin/wt -h /data/db/ load -f error -r index-2-4842695354225906245 Start the server again and run the validate cmd.