diff --git a/backend/watcher.py b/backend/watcher.py
index e7a3c2c..9fdab11 100644
--- a/backend/watcher.py
+++ b/backend/watcher.py
@@ -5,12 +5,17 @@ import os
 import threading
 import time
 from dataclasses import dataclass
+from pathlib import Path
 from typing import Any
 
+try:
+	import smbclient  # type: ignore[import-not-found]
+except ModuleNotFoundError:
+	smbclient = None
 from watchdog.events import FileSystemEvent, FileSystemEventHandler, FileSystemMovedEvent
 from watchdog.observers.polling import PollingObserver
 
-from scanner import resolve_runtime_path, scan_results, path_exists_with_smb
+from scanner import resolve_runtime_path, scan_results
 
 
 LOGGER = logging.getLogger("scheduler.watcher")
@@ -39,6 +44,49 @@ class _ResultDirEventHandler(FileSystemEventHandler):
 			self._on_new_directory(event.dest_path)
 
 
+class _SmbPollerThread(threading.Thread):
+	"""Poll a UNC results directory and trigger a scan when entries change."""
+
+	def __init__(self, unc_path: str, on_change, interval_seconds: float = 5.0):
+		super().__init__(daemon=True, name=f"smb-poller-{unc_path}")
+		self._path = unc_path.rstrip("\\")
+		self._on_change = on_change
+		self._interval_seconds = max(1.0, float(interval_seconds))
+		self._stop_evt = threading.Event()
+
+	def stop(self) -> None:
+		self._stop_evt.set()
+
+	def run(self) -> None:
+		prev = self._snapshot()
+		while not self._stop_evt.wait(self._interval_seconds):
+			try:
+				curr = self._snapshot()
+				added = curr - prev
+				removed = prev - curr
+				if added or removed:
+					LOGGER.info(
+						"SMB directory change detected (%s): +%d -%d",
+						self._path,
+						len(added),
+						len(removed),
+					)
+					self._on_change("smb-directory-change")
+				prev = curr
+			except Exception:
+				LOGGER.exception("SMB poll error for %s", self._path)
+
+	def _snapshot(self) -> set[str]:
+		if smbclient is None:
+			LOGGER.error("smbclient is not installed; SMB polling is unavailable for %s", self._path)
+			return set()
+		try:
+			return {entry.name for entry in smbclient.scandir(self._path) if entry.is_dir()}
+		except Exception:
+			LOGGER.exception("SMB scandir failed for %s", self._path)
+			return set()
+
+
 class ResultDirectoryWatcher:
 	"""Watch DUT/REF result directories and trigger scans when new result folders appear."""
 
@@ -47,7 +95,7 @@ class ResultDirectoryWatcher:
 		self._min_scan_interval_seconds = min_scan_interval_seconds
 		self._lock = threading.RLock()
 		self._scan_lock = threading.Lock()
-		self._observer: PollingObserver | None = None
+		self._watchers: list[Any] = []
 		self._current_config: WatchConfig | None = None
 		self._last_scan_monotonic = 0.0
 
@@ -63,7 +111,7 @@ class ResultDirectoryWatcher:
 		)
 
 		with self._lock:
-			if new_config == self._current_config and self._observer is not None:
+			if new_config == self._current_config and self._watchers:
 				return
 
 			self._stop_locked()
@@ -73,29 +121,89 @@ class ResultDirectoryWatcher:
 				LOGGER.info("result watcher disabled: DUT/REF result directories are not both set")
 				return
 
-			handler = _ResultDirEventHandler(self._on_new_directory)
-			observer = PollingObserver(timeout=self._poll_interval_seconds)
-
 			smb_creds = {
 				"username": new_config.smb_username,
 				"password": new_config.smb_password,
 				"domain": new_config.smb_domain,
 			}
 
-			scheduled_count = 0
-			for result_dir, label in ((dut_dir, "DUT"), (ref_dir, "REF")):
-				if not path_exists_with_smb(result_dir, smb_credentials=smb_creds):
-					LOGGER.warning("%s result directory does not exist yet, skipping watch: %s", label, result_dir)
-					continue
-				observer.schedule(handler, result_dir, recursive=False)
-				scheduled_count += 1
+			local_paths: list[Path] = []
+			smb_paths: list[str] = []
+			seen: set[str] = set()
 
-			if scheduled_count == 0:
+			for result_dir, label in ((dut_dir, "DUT"), (ref_dir, "REF")):
+				is_watchable, reason = _validate_watch_path(result_dir, smb_creds)
+				if not is_watchable:
+					LOGGER.warning(
+						"%s result directory is not watchable, skipping watch: %s (reason: %s)",
+						label,
+						result_dir,
+						reason,
+					)
+					continue
+
+				if _is_unc_path(result_dir):
+					unc = _to_unc_path(result_dir)
+					key = unc.lower()
+					if key not in seen:
+						seen.add(key)
+						smb_paths.append(unc)
+				else:
+					p = Path(result_dir)
+					key = os.path.normcase(str(p))
+					if key not in seen:
+						seen.add(key)
+						local_paths.append(p)
+
+			watchers: list[Any] = []
+
+			if local_paths:
+				handler = _ResultDirEventHandler(self._on_new_directory)
+				observer = PollingObserver(timeout=self._poll_interval_seconds)
+				scheduled_count = 0
+				scheduled_paths: list[str] = []
+				for path in local_paths:
+					try:
+						observer.schedule(handler, str(path), recursive=False)
+						scheduled_count += 1
+						scheduled_paths.append(str(path))
+					except Exception:
+						LOGGER.exception("failed to watch local result directory: %s", path)
+
+				if scheduled_count:
+					try:
+						observer.start()
+						watchers.append(observer)
+						for path in scheduled_paths:
+							print(f"[watcher] Watching local directory: {path}")
+							LOGGER.info("watcher successfully watching local path: %s", path)
+					except Exception:
+						LOGGER.exception("failed to start local result observer")
+						try:
+							observer.stop()
+							observer.join(timeout=5)
+						except Exception:
+							pass
+
+			for unc in smb_paths:
+				registered, reason = _register_smb_session(unc, smb_creds)
+				if not registered:
+					LOGGER.warning("SMB watch skipped for %s (reason: %s)", unc, reason)
+					continue
+				poller = _SmbPollerThread(
+					unc,
+					on_change=lambda reason: self.scan_now(reason=reason),
+					interval_seconds=max(2.0, self._poll_interval_seconds),
+				)
+				poller.start()
+				watchers.append(poller)
+				LOGGER.info("watcher successfully watching SMB path: %s", unc)
+				print(f"[watcher] Watching SMB directory: {unc}")
+			if not watchers:
 				LOGGER.warning("result watcher not started: no valid result directories to watch")
 				return
 
-			observer.start()
-			self._observer = observer
+			self._watchers = watchers
 			LOGGER.info("result watcher started for DUT=%s REF=%s", dut_dir, ref_dir)
 
 		self.scan_now(reason="startup")
@@ -139,11 +247,19 @@ class ResultDirectoryWatcher:
 			self._stop_locked()
 
 	def _stop_locked(self) -> None:
-		observer = self._observer
-		self._observer = None
-		if observer is not None:
-			observer.stop()
-			observer.join(timeout=5)
+		watchers = self._watchers
+		self._watchers = []
+		for watcher in watchers:
+			try:
+				watcher.stop()
+			except Exception:
+				pass
+		for watcher in watchers:
+			try:
+				watcher.join(timeout=5)
+			except Exception:
+				pass
+		if watchers:
 			LOGGER.info("result watcher stopped")
 
 
@@ -167,3 +283,72 @@ def _normalize_watch_path(path_value: Any) -> str:
 	return str(resolve_runtime_path(cleaned)).strip()
 
 
+def _is_unc_path(path_value: str) -> bool:
+	path = str(path_value)
+	return path.startswith("\\\\") or path.startswith("//")
+
+
+def _to_unc_path(path_value: str) -> str:
+	path = str(path_value).replace("/", "\\")
+	if path.startswith("\\\\"):
+		return path
+	if path.startswith("//"):
+		return "\\\\" + path.lstrip("/\\")
+	return "\\\\" + path.lstrip("/\\")
+
+
+def _validate_watch_path(path_value: str, smb_credentials: dict[str, str]) -> tuple[bool, str]:
+	path = str(path_value).strip()
+	if not path:
+		return False, "path is empty"
+
+	if _is_unc_path(path):
+		if smbclient is None:
+			return False, "smbclient is not installed"
+		unc = _to_unc_path(path)
+		registered, reason = _register_smb_session(unc, smb_credentials)
+		if not registered:
+			return False, reason
+		try:
+			# Access one directory entry to validate permissions/connectivity.
+			next(iter(smbclient.scandir(unc)), None)
+		except Exception as exc:
+			return False, f"{type(exc).__name__}: {exc}"
+		return True, "ok"
+
+	if not os.path.exists(path):
+		return False, "path does not exist"
+	if not os.path.isdir(path):
+		return False, "path is not a directory"
+	try:
+		with os.scandir(path):
+			pass
+	except Exception as exc:
+		return False, f"{type(exc).__name__}: {exc}"
+	return True, "ok"
+
+
+def _register_smb_session(unc_path: str, smb_credentials: dict[str, str]) -> tuple[bool, str]:
+	if smbclient is None:
+		return False, "smbclient is not installed"
+
+	server = unc_path[2:].split("\\", 1)[0]
+	if not server:
+		return False, "invalid UNC path (missing server)"
+
+	username = str(smb_credentials.get("username") or "").strip()
+	password = str(smb_credentials.get("password") or "")
+	domain = str(smb_credentials.get("domain") or "").strip()
+	if username and domain and "\\" not in username and "@" not in username:
+		username = f"{domain}\\{username}"
+
+	try:
+		if username:
+			smbclient.register_session(server, username=username, password=password)
+		else:
+			smbclient.register_session(server)
+		return True, "ok"
+	except Exception as exc:
+		return False, f"SMB session registration failed for {server}: {type(exc).__name__}: {exc}"
+
+