diff --git a/changes/bug4457 b/changes/bug4457
new file mode 100644
index 0000000000..fe7c95ff80
--- /dev/null
+++ b/changes/bug4457
@@ -0,0 +1,9 @@
+  o Minor bugfixes:
+    - Initialize Libevent with the EVENT_BASE_FLAG_NOLOCK flag enabled, so
+      that it doesn't attempt to allocate a socketpair. This could cause
+      some problems on windows systems with overzealous firewalls. Fix for
+      bug 4457; workaround for Libevent versions 2.0.1-alpha through
+      2.0.15-stable.
+
+    - Detect failure to initialize Libevent. Better detection for bug 4457.
+
diff --git a/src/common/compat_libevent.c b/src/common/compat_libevent.c
index 3201738701..c53346118f 100644
--- a/src/common/compat_libevent.c
+++ b/src/common/compat_libevent.c
@@ -196,6 +196,7 @@ tor_libevent_initialize(tor_libevent_cfg *torcfg)
 #ifdef HAVE_EVENT2_EVENT_H
   {
     struct event_config *cfg = event_config_new();
+    tor_assert(cfg);
 
 #if defined(MS_WINDOWS) && defined(USE_BUFFEREVENTS)
     if (! torcfg->disable_iocp) {
@@ -224,6 +225,11 @@ tor_libevent_initialize(tor_libevent_cfg *torcfg)
   the_event_base = event_init();
 #endif
 
+  if (!the_event_base) {
+    log_err(LD_GENERAL, "Unable to initialize Libevent: cannot continue.");
+    exit(1);
+  }
+
 #if defined(HAVE_EVENT_GET_VERSION) && defined(HAVE_EVENT_GET_METHOD)
   /* Making this a NOTICE for now so we can link bugs to a libevent versions
    * or methods better. */