diff --git a/frontend/app/(main)/multilang/page.tsx b/frontend/app/(main)/multilang/page.tsx
index 8c54d26d..34a51ec0 100644
--- a/frontend/app/(main)/multilang/page.tsx
+++ b/frontend/app/(main)/multilang/page.tsx
@@ -317,12 +317,16 @@ export default function MultiLangPage() {
 
                   <div>
                     <Label htmlFor="menu">메뉴</Label>
-                    <Select value={selectedMenu} onValueChange={setSelectedMenu}>
+                    {/* Radix UI Select v2.x: 빈 문자열 value="" 금지 → "__all__" 사용 */}
+                    <Select 
+                      value={selectedMenu || "__all__"} 
+                      onValueChange={(value) => setSelectedMenu(value === "__all__" ? "" : value)}
+                    >
                       <SelectTrigger>
                         <SelectValue placeholder="전체 메뉴" />
                       </SelectTrigger>
                       <SelectContent>
-                        <SelectItem value="">전체 메뉴</SelectItem>
+                        <SelectItem value="__all__">전체 메뉴</SelectItem>
                         {menus.map((menu) => (
                           <SelectItem key={menu.code} value={menu.code}>
                             {menu.name}
@@ -334,12 +338,16 @@ export default function MultiLangPage() {
 
                   <div>
                     <Label htmlFor="keyType">키 타입</Label>
-                    <Select value={selectedKeyType} onValueChange={setSelectedKeyType}>
+                    {/* Radix UI Select v2.x: 빈 문자열 value="" 금지 → "__all__" 사용 */}
+                    <Select 
+                      value={selectedKeyType || "__all__"} 
+                      onValueChange={(value) => setSelectedKeyType(value === "__all__" ? "" : value)}
+                    >
                       <SelectTrigger>
                         <SelectValue placeholder="전체 타입" />
                       </SelectTrigger>
                       <SelectContent>
-                        <SelectItem value="">전체 타입</SelectItem>
+                        <SelectItem value="__all__">전체 타입</SelectItem>
                         {keyTypes.map((type) => (
                           <SelectItem key={type.code} value={type.code}>
                             {type.name}
diff --git a/frontend/components/admin/ScreenAssignmentTab.tsx b/frontend/components/admin/ScreenAssignmentTab.tsx
index e6554908..8513e410 100644
--- a/frontend/components/admin/ScreenAssignmentTab.tsx
+++ b/frontend/components/admin/ScreenAssignmentTab.tsx
@@ -172,8 +172,9 @@ export const ScreenAssignmentTab: React.FC<ScreenAssignmentTabProps> = ({ menus
     // });
 
     if (!menuList || menuList.length === 0) {
+      // Radix UI Select v2.x: 빈 문자열 value="" 금지 → "__placeholder__" 사용
       return [
-        <SelectItem key="no-menu" value="" disabled>
+        <SelectItem key="no-menu" value="__placeholder__" disabled>
           메뉴가 없습니다
         </SelectItem>,
       ];
diff --git a/frontend/components/admin/TableLogViewer.tsx b/frontend/components/admin/TableLogViewer.tsx
index 147229df..9f0541b6 100644
--- a/frontend/components/admin/TableLogViewer.tsx
+++ b/frontend/components/admin/TableLogViewer.tsx
@@ -151,12 +151,16 @@ export function TableLogViewer({ tableName, open, onOpenChange }: TableLogViewer
           <div className="grid grid-cols-2 gap-3 md:grid-cols-3">
             <div>
               <label className="mb-1 block text-sm text-gray-600">작업 유형</label>
-              <Select value={operationType} onValueChange={setOperationType}>
+              {/* Radix UI Select v2.x: 빈 문자열 value="" 금지 → "__all__" 사용 */}
+              <Select 
+                value={operationType || "__all__"} 
+                onValueChange={(value) => setOperationType(value === "__all__" ? "" : value)}
+              >
                 <SelectTrigger>
                   <SelectValue placeholder="전체" />
                 </SelectTrigger>
                 <SelectContent>
-                  <SelectItem value="">전체</SelectItem>
+                  <SelectItem value="__all__">전체</SelectItem>
                   <SelectItem value="INSERT">추가</SelectItem>
                   <SelectItem value="UPDATE">수정</SelectItem>
                   <SelectItem value="DELETE">삭제</SelectItem>
diff --git a/frontend/components/dataflow/external-call/DataMappingSettings.tsx b/frontend/components/dataflow/external-call/DataMappingSettings.tsx
index a4e1ea56..01103744 100644
--- a/frontend/components/dataflow/external-call/DataMappingSettings.tsx
+++ b/frontend/components/dataflow/external-call/DataMappingSettings.tsx
@@ -236,12 +236,13 @@ export const DataMappingSettings: React.FC<DataMappingSettingsProps> = ({
                         <SelectValue placeholder={tablesLoading ? "테이블 목록 로딩 중..." : "저장할 테이블을 선택하세요"} />
                       </SelectTrigger>
                       <SelectContent>
+                        {/* Radix UI Select v2.x: 빈 문자열 value="" 금지 → "__placeholder__" 사용 */}
                         {tablesLoading ? (
-                          <SelectItem value="" disabled>
+                          <SelectItem value="__placeholder__" disabled>
                             테이블 목록 로딩 중...
                           </SelectItem>
                         ) : availableTables.length === 0 ? (
-                          <SelectItem value="" disabled>
+                          <SelectItem value="__placeholder__" disabled>
                             사용 가능한 테이블이 없습니다
                           </SelectItem>
                         ) : (
diff --git a/frontend/components/flow/FlowStepPanel.tsx b/frontend/components/flow/FlowStepPanel.tsx
index 855596cb..d861f97b 100644
--- a/frontend/components/flow/FlowStepPanel.tsx
+++ b/frontend/components/flow/FlowStepPanel.tsx
@@ -1173,7 +1173,8 @@ export function FlowStepPanel({
                           기본 REST API 연결
                         </SelectItem>
                       ) : (
-                        <SelectItem value="" disabled>
+                        // Radix UI Select v2.x: 빈 문자열 value="" 금지 → "__placeholder__" 사용
+                        <SelectItem value="__placeholder__" disabled>
                           연결된 REST API가 없습니다
                         </SelectItem>
                       )}
diff --git a/frontend/lib/registry/components/map/MapConfigPanel.tsx b/frontend/lib/registry/components/map/MapConfigPanel.tsx
index 62489274..3f591efc 100644
--- a/frontend/lib/registry/components/map/MapConfigPanel.tsx
+++ b/frontend/lib/registry/components/map/MapConfigPanel.tsx
@@ -315,16 +315,17 @@ export default function MapConfigPanel({ config, onChange }: MapConfigPanelProps
         {/* 라벨 컬럼 (선택) */}
         <div className="space-y-2 mb-3">
           <Label>라벨 컬럼 (선택사항)</Label>
+          {/* Radix UI Select v2.x: 빈 문자열 value="" 금지 → "__none__" 사용 */}
           <Select
-            value={config.dataSource?.labelColumn || ""}
-            onValueChange={(value) => updateConfig("dataSource.labelColumn", value)}
+            value={config.dataSource?.labelColumn || "__none__"}
+            onValueChange={(value) => updateConfig("dataSource.labelColumn", value === "__none__" ? "" : value)}
             disabled={isLoadingColumns || !config.dataSource?.tableName}
           >
             <SelectTrigger>
               <SelectValue placeholder="라벨 컬럼 선택" />
             </SelectTrigger>
             <SelectContent>
-              <SelectItem value="">선택 안 함</SelectItem>
+              <SelectItem value="__none__">선택 안 함</SelectItem>
               {columns.map((col) => (
                 <SelectItem key={col.column_name} value={col.column_name}>
                   {col.column_name} ({col.data_type})
@@ -337,16 +338,17 @@ export default function MapConfigPanel({ config, onChange }: MapConfigPanelProps
         {/* 상태 컬럼 (선택) */}
         <div className="space-y-2 mb-3">
           <Label>상태 컬럼 (선택사항)</Label>
+          {/* Radix UI Select v2.x: 빈 문자열 value="" 금지 → "__none__" 사용 */}
           <Select
-            value={config.dataSource?.statusColumn || ""}
-            onValueChange={(value) => updateConfig("dataSource.statusColumn", value)}
+            value={config.dataSource?.statusColumn || "__none__"}
+            onValueChange={(value) => updateConfig("dataSource.statusColumn", value === "__none__" ? "" : value)}
             disabled={isLoadingColumns || !config.dataSource?.tableName}
           >
             <SelectTrigger>
               <SelectValue placeholder="상태 컬럼 선택" />
             </SelectTrigger>
             <SelectContent>
-              <SelectItem value="">선택 안 함</SelectItem>
+              <SelectItem value="__none__">선택 안 함</SelectItem>
               {columns.map((col) => (
                 <SelectItem key={col.column_name} value={col.column_name}>
                   {col.column_name} ({col.data_type})
diff --git a/frontend/lib/registry/components/universal-form-modal/modals/FieldDetailSettingsModal.tsx b/frontend/lib/registry/components/universal-form-modal/modals/FieldDetailSettingsModal.tsx
index f33f5405..2404cc4c 100644
--- a/frontend/lib/registry/components/universal-form-modal/modals/FieldDetailSettingsModal.tsx
+++ b/frontend/lib/registry/components/universal-form-modal/modals/FieldDetailSettingsModal.tsx
@@ -550,12 +550,12 @@ export function FieldDetailSettingsModal({
                             <Label className="text-[10px]">저장할 컬럼</Label>
                             {selectTableColumns.length > 0 ? (
                               <Select
-                                value={localField.selectOptions?.saveColumn || ""}
+                                value={localField.selectOptions?.saveColumn || "__default__"}
                                 onValueChange={(value) =>
                                   updateField({
                                     selectOptions: {
                                       ...localField.selectOptions,
-                                      saveColumn: value,
+                                      saveColumn: value === "__default__" ? "" : value,
                                     },
                                   })
                                 }
@@ -564,7 +564,7 @@ export function FieldDetailSettingsModal({
                                   <SelectValue placeholder="컬럼 선택 (미선택 시 조인 컬럼 저장)" />
                                 </SelectTrigger>
                                 <SelectContent>
-                                  <SelectItem value="">조인 컬럼 사용 (기본)</SelectItem>
+                                  <SelectItem value="__default__">조인 컬럼 사용 (기본)</SelectItem>
                                   {selectTableColumns.map((col) => (
                                     <SelectItem key={col.name} value={col.name}>
                                       {col.name}