diff --git a/lldb/include/lldb/Host/windows/HostProcessWindows.h b/lldb/include/lldb/Host/windows/HostProcessWindows.h
index 4178956f5617..925d565c275e 100644
--- a/lldb/include/lldb/Host/windows/HostProcessWindows.h
+++ b/lldb/include/lldb/Host/windows/HostProcessWindows.h
@@ -30,8 +30,9 @@ public:
   lldb::pid_t GetProcessId() const override;
   bool IsRunning() const override;
 
-  HostThread StartMonitoring(const Host::MonitorChildProcessCallback &callback,
-                             bool monitor_signals) override;
+  virtual llvm::Expected<HostThread>
+  StartMonitoring(const Host::MonitorChildProcessCallback &callback,
+                  bool monitor_signals) override;
 
 private:
   static lldb::thread_result_t MonitorThread(void *thread_arg);
diff --git a/lldb/source/Host/windows/HostProcessWindows.cpp b/lldb/source/Host/windows/HostProcessWindows.cpp
index c422a86683af..d7484f8a89b7 100644
--- a/lldb/source/Host/windows/HostProcessWindows.cpp
+++ b/lldb/source/Host/windows/HostProcessWindows.cpp
@@ -94,7 +94,7 @@ llvm::Expected<HostThread> HostProcessWindows::StartMonitoring(
                         &info->process_handle, 0, FALSE, DUPLICATE_SAME_ACCESS))
     result = ThreadLauncher::LaunchThread("ChildProcessMonitor",
                                           HostProcessWindows::MonitorThread,
-                                          info, nullptr);
+                                          info);
   return result;
 }