diff --git a/unsupported/Eigen/CXX11/src/ThreadPool/NonBlockingThreadPool.h b/unsupported/Eigen/CXX11/src/ThreadPool/NonBlockingThreadPool.h
index 9f4e318e5..354bce52a 100644
--- a/unsupported/Eigen/CXX11/src/ThreadPool/NonBlockingThreadPool.h
+++ b/unsupported/Eigen/CXX11/src/ThreadPool/NonBlockingThreadPool.h
@@ -29,6 +29,8 @@ class NonBlockingThreadPoolTempl : public Eigen::ThreadPoolInterface {
         spinning_(0),
         done_(false),
         ec_(waiters_) {
+    waiters_.resize(num_threads);
+
     // Calculate coprimes of num_threads.
     // Coprimes are used for a random walk over all threads in Steal
     // and NonEmptyQueueIndex. Iteration is based on the fact that if we take
diff --git a/unsupported/test/cxx11_eventcount.cpp b/unsupported/test/cxx11_eventcount.cpp
index 366df9cee..3b598bf42 100644
--- a/unsupported/test/cxx11_eventcount.cpp
+++ b/unsupported/test/cxx11_eventcount.cpp
@@ -26,6 +26,7 @@ int rand_reentrant(unsigned int* s) {
 static void test_basic_eventcount()
 {
   MaxSizeVector<EventCount::Waiter> waiters(1);
+  waiters.resize(1);
   EventCount ec(waiters);
   EventCount::Waiter& w = waiters[0];
   ec.Notify(false);
@@ -82,6 +83,7 @@ static void test_stress_eventcount()
   static const int kQueues = 10;
 
   MaxSizeVector<EventCount::Waiter> waiters(kThreads);
+  waiters.resize(kThreads);
   EventCount ec(waiters);
   TestQueue queues[kQueues];