diff --git a/remoting/host/win/unprivileged_process_delegate.cc b/remoting/host/win/unprivileged_process_delegate.cc
index b82eceb72ae27..1d21a2f68e52d 100644
--- a/remoting/host/win/unprivileged_process_delegate.cc
+++ b/remoting/host/win/unprivileged_process_delegate.cc
@@ -401,6 +401,13 @@ void UnprivilegedProcessDelegate::KillProcess() {
   CloseChannel();
   event_handler_ = nullptr;
 
+  // Stop the ObjectWatcher before closing the handle it is waiting on.
+  // Per base/win/object_watcher.h, closing a handle while a wait is pending is
+  // undefined behavior (MSDN: RegisterWaitForSingleObject). This also prevents
+  // a second StartWatchingOnce() on the same watcher when the launcher
+  // relaunches the worker through this same delegate instance.
+  process_watcher_.StopWatching();
+
   if (worker_process_.is_valid()) {
     TerminateProcess(worker_process_.Get(), CONTROL_C_EXIT);
     worker_process_.Close();
@@ -454,9 +461,12 @@ void UnprivilegedProcessDelegate::ReportProcessLaunched(
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
   // Report a handle that can be used to wait for the worker process completion,
-  // query information about the process and duplicate handles.
-  DWORD desired_access =
-      SYNCHRONIZE | PROCESS_DUP_HANDLE | PROCESS_QUERY_INFORMATION;
+  // query information about the process, duplicate handles, and terminate it.
+  // PROCESS_TERMINATE is required so that KillProcess() can forcibly reap the
+  // worker after the kill timer fires; without it TerminateProcess() fails
+  // with ERROR_ACCESS_DENIED and a misbehaving low-IL worker survives.
+  DWORD desired_access = SYNCHRONIZE | PROCESS_DUP_HANDLE |
+                         PROCESS_QUERY_INFORMATION | PROCESS_TERMINATE;
   HANDLE temp_handle;
   if (!DuplicateHandle(GetCurrentProcess(), worker_process.Get(),
                        GetCurrentProcess(), &temp_handle, desired_access, FALSE,