diff --git a/cmd/util/ledger/migrations/deduplicate_contract_names_migration.go b/cmd/util/ledger/migrations/deduplicate_contract_names_migration.go
index 5d79da0590c..80707e39d95 100644
--- a/cmd/util/ledger/migrations/deduplicate_contract_names_migration.go
+++ b/cmd/util/ledger/migrations/deduplicate_contract_names_migration.go
@@ -1,14 +1,11 @@
 package migrations
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 
-	"github.com/rs/zerolog"
-	"github.com/rs/zerolog/log"
-
 	"github.com/fxamacker/cbor/v2"
+	"github.com/rs/zerolog"
 
 	"github.com/onflow/cadence/runtime/common"
 
@@ -26,6 +23,10 @@ type DeduplicateContractNamesMigration struct {
 	log zerolog.Logger
 }
 
+func (d *DeduplicateContractNamesMigration) Close() error {
+	return nil
+}
+
 func (d *DeduplicateContractNamesMigration) InitMigration(
 	log zerolog.Logger,
 	_ []*ledger.Payload,
@@ -56,46 +57,40 @@ func (d *DeduplicateContractNamesMigration) MigrateAccount(
 	if err != nil {
 		return nil, fmt.Errorf("failed to get contract names: %w", err)
 	}
-	if len(contractNames) == 0 {
+	if len(contractNames) == 1 {
 		return payloads, nil
 	}
 
-	contractNamesSet := make(map[string]struct{})
-	removeIndexes := make([]int, 0)
-	for i, name := range contractNames {
-		if _, ok := contractNamesSet[name]; ok {
-			// duplicate contract name
-			removeIndexes = append(removeIndexes, i)
+	var foundDuplicate bool
+	i := 1
+	for i < len(contractNames) {
+		if contractNames[i-1] != contractNames[i] {
+			i++
 			continue
 		}
-
-		contractNamesSet[name] = struct{}{}
+		// Found duplicate (contactNames[i-1] == contactNames[i])
+		// Remove contractNames[i]
+		copy(contractNames[i:], contractNames[i+1:])
+		contractNames = contractNames[:len(contractNames)-1]
+		foundDuplicate = true
 	}
 
-	if len(removeIndexes) == 0 {
+	if !foundDuplicate {
 		return payloads, nil
 	}
 
-	log.Info().
+	d.log.Info().
 		Str("address", address.Hex()).
 		Strs("contract_names", contractNames).
 		Msg("removing duplicate contract names")
 
-	// remove the duplicate contract names, keeping the original order
-	for i := len(removeIndexes) - 1; i >= 0; i-- {
-		contractNames = append(contractNames[:removeIndexes[i]], contractNames[removeIndexes[i]+1:]...)
-	}
-
-	var buf bytes.Buffer
-	cborEncoder := cbor.NewEncoder(&buf)
-	err = cborEncoder.Encode(contractNames)
+	newContractNames, err := cbor.Marshal(contractNames)
 	if err != nil {
 		return nil, fmt.Errorf(
 			"cannot encode contract names: %s",
 			contractNames,
 		)
 	}
-	newContractNames := buf.Bytes()
 
 	id := flow.ContractNamesRegisterID(flowAddress)
 	err = accounts.SetValue(id, newContractNames)