diff --git a/hermes_cli/main.py b/hermes_cli/main.py
index 68432c3aa00..e11154206e1 100644
--- a/hermes_cli/main.py
+++ b/hermes_cli/main.py
@@ -7665,8 +7665,11 @@ def _detect_concurrent_hermes_instances(
 
     This helper enumerates processes whose ``exe`` matches one of the venv's
     shims (``hermes.exe`` / ``hermes-gateway.exe``) and returns ``(pid,
-    process_name)`` pairs. The caller's own PID is excluded so the running
-    ``hermes update`` invocation never reports itself.
+    process_name)`` pairs. The caller's own PID and its entire ancestor
+    chain are excluded so the running ``hermes update`` invocation never
+    reports itself — this matters on Windows where the setuptools .exe
+    launcher (``hermes.exe``) is a separate process from the Python
+    interpreter it loads (``python.exe``).
 
     Returns an empty list off-Windows, on missing psutil, or when no other
     instances exist. Never raises — process enumeration is best-effort.
@@ -7679,8 +7682,32 @@ def _detect_concurrent_hermes_instances(
     except Exception:
         return []
 
-    if exclude_pid is None:
-        exclude_pid = os.getpid()
+    # Build a set of PIDs to exclude: the Python process itself plus its
+    # entire parent chain. On Windows the setuptools-generated hermes.exe
+    # launcher is a separate native process that spawns python.exe (the
+    # interpreter that runs our code).  os.getpid() returns the Python PID,
+    # but the launcher (which holds the file lock) is the parent.  Without
+    # walking the parent chain, every ``hermes update`` reports its own
+    # launcher as a concurrent instance — a false positive.
+    if exclude_pid is not None:
+        exclude_pids: set[int] = {exclude_pid}
+    else:
+        exclude_pids = {os.getpid()}
+    try:
+        current = psutil.Process(next(iter(exclude_pids)))
+        while True:
+            try:
+                parent = current.parent()
+            except (psutil.NoSuchProcess, psutil.AccessDenied):
+                break
+            if parent is None or parent.pid <= 0:
+                break
+            if parent.pid in exclude_pids:
+                break  # loop detected
+            exclude_pids.add(parent.pid)
+            current = parent
+    except (psutil.NoSuchProcess, psutil.AccessDenied, ValueError):
+        pass
 
     # Resolve every shim path to its canonical form once for cheap comparison.
     shim_paths: set[str] = set()
@@ -7705,7 +7732,7 @@ def _detect_concurrent_hermes_instances(
             continue
         pid = info.get("pid")
         exe = info.get("exe")
-        if not exe or pid is None or pid == exclude_pid:
+        if not exe or pid is None or pid in exclude_pids:
             continue
         try:
             exe_norm = str(Path(exe).resolve()).lower()