diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 037b84e80476f0121c5483bc51c16ad475aff885..2fe374badf13112132d66f0e69f3c1fd3d1dc526 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -36,6 +36,7 @@ variables:
       artifacts: false
   script:
     - echo "Creating artifact for $TARGET_OS"
+    - export HOME=/tmp
     - pip install -r requirements.txt
     - pyinstaller --onefile ${BINARY_NAME}.py
     - export TS=$(date +%Y-%m-%d_%H%M)
diff --git a/.pylintrc b/.pylintrc
index 10191476ffc02f703d93f153e1c5bdd292dd43e9..120adfdbbc3043205e7ba5901b8235258806c84a 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -3,7 +3,7 @@
 # disable=too-many-instance-attributes, too-many-arguments, too-many-positional-arguments, too-many-locals
 # Same with above
 # Disable specific message IDs.
-disable=R0902, R0913, R0915, R0917, R0914
+disable=R0902, R0913, R0915, R0917, R0914, R0912
 
 [FORMAT]
 # Maximum number of characters on a single line.
diff --git a/load_check.py b/load_check.py
index 7b429c7c4f1f27ed63840eaccb8b5ed535ba64d4..68bb71404e95b45c6c53a1729e47c648674b07e9 100644
--- a/load_check.py
+++ b/load_check.py
@@ -23,8 +23,20 @@ class MultipleTest(unittest.TestCase):
     def _get_user_inputs(self):
         """Helper method to get user inputs and set up initial configuration."""
         # Test case user input
-        print("1. [필수 입력] Chrome 위치 (e.g., /opt/chrome-linux64/chrome, D:\\tmp\\chrome-win64\\chrome.exe): ")
-        self.binary_location = input().strip()
+        while True:
+            print("1. [필수 입력] Chrome 위치 (e.g., /opt/chrome-linux64/chrome, D:\\tmp\\chrome-win64\\chrome.exe): ")
+            chrome_path = input().strip()
+
+            if not chrome_path:
+                print("잘못 입력하였습니다. 다시 입력해주세요.\n")
+                continue
+
+            if os.path.exists(chrome_path) and os.path.isfile(chrome_path):
+                self.binary_location = chrome_path
+                break
+
+            print(f"입력한 경로가 존재하지 않거나 파일이 아닙니다: {chrome_path}")
+            print("다시 입력해주세요.\n")
 
         print("\n2. [필수 입력] 테스트 대상 웹 (e.g., https://example.com:8443/): ")
         self.dc_address = input()
@@ -34,50 +46,41 @@ class MultipleTest(unittest.TestCase):
             print("EMS 접속이 원할하지 않습니다. 프로그램을 종료합니다")
             sys.exit(1)
 
-        # A list is created to store multiple account configurations.
         self.account_configs = []
-        # print("\n[필수 입력] 계정 정보를 한 줄씩 입력하세요. (포맷: 유형 / 아이디, 비번 / 세션 수)")
-        print("\n3. [필수 입력] 계정유형(1-어드민,2-(지역)관리자,3-사용자) / 계정 접속정보 / 커넥션 비중")
-        print("ex) 1 / admin, admin / 3")
-        print("ex) 2 / watchall, watchall / 3")
-        print("ex) 3 / monitor, monitor / 4")
-        print("입력을 마치려면 빈 줄에서 엔터키를 누르세요.")
-
-        # A loop reads each line of input until an empty line is entered.
+        print("\n3. [필수 입력] 계정유형(1-어드민,2-(지역)관리자,3-사용자) / 계정 접속정보")
+        print("형식 예시: 1 / admin, admin")
+
         while True:
             user_input = input("").strip()
-            if not user_input:
-                # Exit the loop if the input is empty.
-                if not self.account_configs:
-                    print("입력된 계정 정보가 없습니다. 프로그램을 종료합니다.")
-                    sys.exit(1)
-                break
             try:
-                # Each line is parsed and appended to the list as a dictionary.
-                parts = user_input.split(' / ')
-                account_type = int(parts[0].strip())
-                credentials = parts[1].split(',')
-                username = credentials[0].strip()
-                password = credentials[1].strip()
-                duplicate_count = int(parts[2].strip())
-
-                config = {
-                    "account_type": account_type,
-                    "username": username,
-                    "password": password,
-                    "duplicate_count": duplicate_count
-                }
+                config = self._parse_account_line(user_input)
                 self.account_configs.append(config)
-            except (ValueError, IndexError):
-                print(f"잘못된 입력 형식입니다: '{user_input}'. 해당 줄은 무시됩니다.")
+                # success -> stop re-prompting
+                break
+            except ValueError as e:
+                print(f"입력 형식 오류: {e}. 다시 입력하세요.")
 
         # New inputs for connection management
-        print("\n4. [선택] 테스트 유형(기본값: 일반접속): 일반 접속(1), 일시 접속(2), 부하 화면 접근(3)")
-        try:
-            self.function_to_execute = int(input().strip())
-        except ValueError:
-            print("잘못된 입력입니다. 기본값 '일반 접속(1)'으로 설정합니다.")
+        print("\n4. [선택] 테스트 유형(기본값: 일반접속): 일반 접속(1), 대시보드 부하(2)")
+        user_input = input().strip()
+
+        if not user_input:
+            # ✅ empty input → default
+            print("입력이 비어있습니다. 기본값 '일반 접속(1)'으로 설정합니다.")
             self.function_to_execute = 1
+        else:
+            try:
+                choice = int(user_input)
+                # if choice in (1, 2):
+                if choice == 1:
+                    self.function_to_execute = choice
+                else:
+                    print("현재 스크립트는 일반 접속 방법만 지원합니다. '일반 접속(1)'으로 설정합니다.")
+                    self.function_to_execute = 1
+            except ValueError:
+                print("잘못 입력하셨습니다. 기본값 '일반 접속(1)'으로 설정합니다.")
+                self.function_to_execute = 1
+
 
         print("\n5. [선택] 커넥션 수 / 테스트 시간(분)(기본값: 30개 / 120분)")
         try:
@@ -103,6 +106,51 @@ class MultipleTest(unittest.TestCase):
         os.makedirs(self.screenshots_folder, exist_ok=True)
         self.screenshot_base_dir = self.screenshots_folder
 
+        # Debug screenshot toggle:
+        # - Environment variable SCREENSHOT_ALL=1 / true / y will enable all screenshots (non-interactive)
+        # - Otherwise ask interactively (default No)
+        env_flag = os.getenv("SCREENSHOT_ALL", "").lower()
+        if env_flag in ("1", "true", "y", "yes"):
+            self.screenshot_all = True
+            print("[INFO] SCREENSHOT_ALL environment variable enabled: saving screenshots for ALL drivers (debug mode).")
+        else:
+            print("\n6. [선택] 모든 세션에서 스크린샷을 저장하시겠습니까? (y/N): ")
+            ans = input().strip().lower()
+            self.screenshot_all = ans in ("y", "yes")
+            if self.screenshot_all:
+                print("[INFO] Debug mode ON: saving screenshots for ALL drivers.")
+            else:
+                print("[INFO] Default mode: saving screenshots only for first and last drivers.")
+
+    def _parse_account_line(self, user_input: str):
+        """Parse a single account config line in the format:
+           '<type> / username, password'
+           Returns a dict on success or raises ValueError on bad format.
+        """
+        if not user_input or not user_input.strip():
+            raise ValueError("다시 입력해 주십시요.")
+
+        parts = user_input.split(' / ')
+        if len(parts) < 2:
+            raise ValueError("입력 형식이 잘못되었습니다. 예시: 1 / admin, admin")
+
+        try:
+            account_type = int(parts[0].strip())
+            credentials = parts[1].split(',')
+            if len(credentials) < 2:
+                raise ValueError("아이디와 비밀번호를 쉼표로 구분하세요. 예시: admin, admin")
+            username = credentials[0].strip()
+            password = credentials[1].strip()
+        except ValueError as e:
+            # Preserve the original exception context for better debugging and satisfy pylint W0707
+            raise ValueError(f"입력 형식 오류: {e}") from e
+
+        return {
+            "account_type": account_type,
+            "username": username,
+            "password": password,
+        }
+
     def check_http_status(self, url: str, max_retry: int = 3, ignore_cert: bool = True) -> bool:
         """
         Checks the HTTP status of the given URL.
@@ -158,20 +206,46 @@ class MultipleTest(unittest.TestCase):
         self.accept_next_alert = True
 
     def _take_screenshot(self, driver, action_name):
-        """Saves a screenshot with a unique, descriptive filename."""
+        """Saves screenshots according to the screenshot_all flag.
+
+        - If self.screenshot_all is True -> save for every driver.
+        - Otherwise only save for driver.instance_number == 1 or == self.max_connections.
+        """
         try:
+            inst = getattr(driver, "instance_number", None)
+            if inst is None:
+                # No instance number set; skip silently
+                return
+
+            # If debug flag set -> save for everyone
+            if getattr(self, "screenshot_all", False):
+                do_save = True
+            else:
+                last_inst = getattr(self, "max_connections", None)
+                # Default behavior: only save for instance 1 and planned last instance
+                do_save = (inst == 1) or (last_inst is not None and inst == last_inst)
+
+            if not do_save:
+                return
+
+            # proceed to save screenshot for allowed instances
             time.sleep(0.2)
-            session_folder = os.path.join(self.screenshot_base_dir, f"session_{driver.instance_number}")
+            session_folder = os.path.join(self.screenshot_base_dir, f"session_{inst}")
             os.makedirs(session_folder, exist_ok=True)
-            counter = getattr(driver, 'screenshot_counter', 0) + 1
-            setattr(driver, 'screenshot_counter', counter)
+
+            counter = getattr(driver, "screenshot_counter", 0) + 1
+            setattr(driver, "screenshot_counter", counter)
             counter_str = str(counter).zfill(4)
             filename = os.path.join(session_folder, f"{counter_str}_{action_name}.png")
-            time.sleep(3) # Set common wait time before save screenshot(except custom dashboard)
+
+            # allow page to settle (your previous behavior)
+            time.sleep(3)
             driver.save_screenshot(filename)
+            # optionally show debug
             # print(f"Screenshot saved: {filename}")
-        except (FileNotFoundError, PermissionError):
-            print(f"Error saving screenshot for session {driver.instance_number}")
+
+        except (FileNotFoundError, PermissionError) as e:
+            print(f"Error saving screenshot for session {getattr(driver, 'instance_number', 'unknown')}: {e}")
 
     def _interact_with_time_filters(self, driver):
         """
@@ -521,7 +595,11 @@ class MultipleTest(unittest.TestCase):
         # Guest Mode
         options.add_argument('--guest')
         options.add_argument("--window-size=1920,1080")
-        options.add_argument("--headless=new")
+        headless = os.getenv("HEADLESS", "").lower()
+        if headless in ("0", "false", "n", "no"):
+            pass
+        else:
+            options.add_argument("--headless=new")
         # options.add_argument("--disable-gpu")
         options.binary_location = self.binary_location
         # Linux Only