diff --git a/backend/internal/handler/admin/admin_service_stub_test.go b/backend/internal/handler/admin/admin_service_stub_test.go
index c36e530d..f3b99ddb 100644
--- a/backend/internal/handler/admin/admin_service_stub_test.go
+++ b/backend/internal/handler/admin/admin_service_stub_test.go
@@ -10,23 +10,23 @@ import (
 )
 
 type stubAdminService struct {
-	users            []service.User
-	apiKeys          []service.APIKey
-	groups           []service.Group
-	accounts         []service.Account
-	proxies          []service.Proxy
-	proxyCounts      []service.ProxyWithAccountCount
-	redeems          []service.RedeemCode
-	createdAccounts  []*service.CreateAccountInput
-	createdProxies   []*service.CreateProxyInput
-	updatedProxyIDs  []int64
-	updatedProxies   []*service.UpdateProxyInput
-	testedProxyIDs   []int64
+	users                []service.User
+	apiKeys              []service.APIKey
+	groups               []service.Group
+	accounts             []service.Account
+	proxies              []service.Proxy
+	proxyCounts          []service.ProxyWithAccountCount
+	redeems              []service.RedeemCode
+	createdAccounts      []*service.CreateAccountInput
+	createdProxies       []*service.CreateProxyInput
+	updatedProxyIDs      []int64
+	updatedProxies       []*service.UpdateProxyInput
+	testedProxyIDs       []int64
 	createAccountErr     error
 	updateAccountErr     error
 	bulkUpdateAccountErr error
 	checkMixedErr        error
-	lastMixedCheck   struct {
+	lastMixedCheck       struct {
 		accountID int64
 		platform  string
 		groupIDs  []int64
diff --git a/backend/internal/service/admin_service.go b/backend/internal/service/admin_service.go
index b3ace93f..f9995d04 100644
--- a/backend/internal/service/admin_service.go
+++ b/backend/internal/service/admin_service.go
@@ -2288,41 +2288,6 @@ func (s *adminServiceImpl) checkMixedChannelRisk(ctx context.Context, currentAcc
 	return nil
 }
 
-func (s *adminServiceImpl) preloadMixedChannelRiskData(ctx context.Context, groupIDs []int64) (map[int64][]Account, map[int64]string, error) {
-	accountsByGroup := make(map[int64][]Account)
-	groupNameByID := make(map[int64]string)
-	if len(groupIDs) == 0 {
-		return accountsByGroup, groupNameByID, nil
-	}
-
-	seen := make(map[int64]struct{}, len(groupIDs))
-	for _, groupID := range groupIDs {
-		if groupID <= 0 {
-			continue
-		}
-		if _, ok := seen[groupID]; ok {
-			continue
-		}
-		seen[groupID] = struct{}{}
-
-		accounts, err := s.accountRepo.ListByGroup(ctx, groupID)
-		if err != nil {
-			return nil, nil, fmt.Errorf("get accounts in group %d: %w", groupID, err)
-		}
-		accountsByGroup[groupID] = accounts
-
-		group, err := s.groupRepo.GetByID(ctx, groupID)
-		if err != nil {
-			continue
-		}
-		if group != nil {
-			groupNameByID[groupID] = group.Name
-		}
-	}
-
-	return accountsByGroup, groupNameByID, nil
-}
-
 func (s *adminServiceImpl) validateGroupIDsExist(ctx context.Context, groupIDs []int64) error {
 	if len(groupIDs) == 0 {
 		return nil
@@ -2352,71 +2317,6 @@ func (s *adminServiceImpl) validateGroupIDsExist(ctx context.Context, groupIDs [
 	return nil
 }
 
-func (s *adminServiceImpl) checkMixedChannelRiskWithPreloaded(currentAccountID int64, currentAccountPlatform string, groupIDs []int64, accountsByGroup map[int64][]Account, groupNameByID map[int64]string) error {
-	currentPlatform := getAccountPlatform(currentAccountPlatform)
-	if currentPlatform == "" {
-		return nil
-	}
-
-	for _, groupID := range groupIDs {
-		accounts := accountsByGroup[groupID]
-		for _, account := range accounts {
-			if currentAccountID > 0 && account.ID == currentAccountID {
-				continue
-			}
-
-			otherPlatform := getAccountPlatform(account.Platform)
-			if otherPlatform == "" {
-				continue
-			}
-
-			if currentPlatform != otherPlatform {
-				groupName := fmt.Sprintf("Group %d", groupID)
-				if name := strings.TrimSpace(groupNameByID[groupID]); name != "" {
-					groupName = name
-				}
-
-				return &MixedChannelError{
-					GroupID:         groupID,
-					GroupName:       groupName,
-					CurrentPlatform: currentPlatform,
-					OtherPlatform:   otherPlatform,
-				}
-			}
-		}
-	}
-
-	return nil
-}
-
-func updateMixedChannelPreloadedAccounts(accountsByGroup map[int64][]Account, groupIDs []int64, accountID int64, platform string) {
-	if len(groupIDs) == 0 || accountID <= 0 || platform == "" {
-		return
-	}
-	for _, groupID := range groupIDs {
-		if groupID <= 0 {
-			continue
-		}
-		accounts := accountsByGroup[groupID]
-		found := false
-		for i := range accounts {
-			if accounts[i].ID != accountID {
-				continue
-			}
-			accounts[i].Platform = platform
-			found = true
-			break
-		}
-		if !found {
-			accounts = append(accounts, Account{
-				ID:       accountID,
-				Platform: platform,
-			})
-		}
-		accountsByGroup[groupID] = accounts
-	}
-}
-
 // CheckMixedChannelRisk checks whether target groups contain mixed channels for the current account platform.
 func (s *adminServiceImpl) CheckMixedChannelRisk(ctx context.Context, currentAccountID int64, currentAccountPlatform string, groupIDs []int64) error {
 	return s.checkMixedChannelRisk(ctx, currentAccountID, currentAccountPlatform, groupIDs)