diff --git a/clang/lib/DirectoryWatcher/windows/DirectoryWatcher-windows.cpp b/clang/lib/DirectoryWatcher/windows/DirectoryWatcher-windows.cpp
index 6bcfb86e7f99..847d20bfbb6f 100644
--- a/clang/lib/DirectoryWatcher/windows/DirectoryWatcher-windows.cpp
+++ b/clang/lib/DirectoryWatcher/windows/DirectoryWatcher-windows.cpp
@@ -40,6 +40,7 @@ class DirectoryWatcherWindows : public clang::DirectoryWatcher {
 
   std::mutex Mutex;
   bool WatcherActive = false;
+  bool NotifierActive = false;
   std::condition_variable Ready;
 
   class EventQueue {
@@ -117,7 +118,9 @@ DirectoryWatcherWindows::DirectoryWatcherWindows(
   });
 
   std::unique_lock<std::mutex> lock(Mutex);
-  Ready.wait(lock, [this] { return this->WatcherActive; });
+  Ready.wait(lock, [this] {
+    return this->WatcherActive && this->NotifierActive;
+  });
 }
 
 DirectoryWatcherWindows::~DirectoryWatcherWindows() {
@@ -227,6 +230,12 @@ void DirectoryWatcherWindows::NotifierThreadProc(bool WaitForInitialSync) {
   if (!WaitForInitialSync)
     this->InitialScan();
 
+  {
+    std::unique_lock<std::mutex> lock(Mutex);
+    NotifierActive = true;
+  }
+  Ready.notify_one();
+
   while (true) {
     DirectoryWatcher::Event E = Q.pop_front();
     Callback(E, /*IsInitial=*/false);