diff --git a/hermes_cli/doctor.py b/hermes_cli/doctor.py
index fce081ebe0b6..f1dd38bb9ad0 100644
--- a/hermes_cli/doctor.py
+++ b/hermes_cli/doctor.py
@@ -887,11 +887,13 @@ def run_doctor(args):
     if env_path.exists():
         check_ok(f"{_DHH}/.env file exists")
         
-        # Check for common issues. Pin encoding to UTF-8 because .env files are
-        # written as UTF-8 everywhere in the codebase, while Path.read_text()
-        # defaults to the system locale — which crashes on non-UTF-8 Windows
-        # locales (e.g. GBK) as soon as the file contains any non-ASCII byte.
-        content = env_path.read_text(encoding="utf-8")
+        # Prefer UTF-8 (.env is written as UTF-8 elsewhere). Fall back to
+        # latin-1 for Windows Notepad/cp1252 files that are not valid UTF-8 —
+        # matches hermes_cli.env_loader._load_dotenv_with_fallback.
+        try:
+            content = env_path.read_text(encoding="utf-8")
+        except UnicodeDecodeError:
+            content = env_path.read_text(encoding="latin-1")
         if _has_provider_env_config(content):
             check_ok("API key or custom endpoint configured")
         else:
diff --git a/tests/hermes_cli/test_doctor.py b/tests/hermes_cli/test_doctor.py
index 2fa798a08159..c439aaf0cee5 100644
--- a/tests/hermes_cli/test_doctor.py
+++ b/tests/hermes_cli/test_doctor.py
@@ -126,6 +126,30 @@ class TestDoctorEnvFileEncoding:
             doctor_mod.run_doctor(Namespace(fix=False))
 
 
+
+    def test_doctor_reads_invalid_utf8_env_via_latin1_fallback(
+        self, monkeypatch, tmp_path
+    ):
+        """cp1252/latin-1 .env with ASCII provider hints must not abort doctor."""
+        hermes_home = tmp_path / ".hermes"
+        hermes_home.mkdir()
+        env_path = hermes_home / ".env"
+        # 0xff is invalid UTF-8; latin-1 decodes it. Keep an ASCII provider key
+        # so the scan still reports a configured endpoint/key.
+        env_path.write_bytes(b"OPENAI_API_KEY=sk-test\xff\n")
+
+        monkeypatch.setattr(doctor_mod, "HERMES_HOME", hermes_home)
+
+        fake_model_tools = types.SimpleNamespace(
+            check_tool_availability=lambda *a, **kw: (_ for _ in ()).throw(SystemExit(0)),
+            TOOLSET_REQUIREMENTS={},
+        )
+        monkeypatch.setitem(sys.modules, "model_tools", fake_model_tools)
+
+        with pytest.raises(SystemExit):
+            doctor_mod.run_doctor(Namespace(fix=False))
+
+
 class TestDoctorToolAvailabilityOverrides:
     def test_marks_honcho_available_when_configured(self, monkeypatch):
         monkeypatch.setattr(doctor, "_honcho_is_configured_for_doctor", lambda: True)