diff --git a/libcef/common/main_delegate.cc b/libcef/common/main_delegate.cc
index b3d29b5d9..0da8ec880 100644
--- a/libcef/common/main_delegate.cc
+++ b/libcef/common/main_delegate.cc
@@ -562,6 +562,7 @@ int CefMainDelegate::RunProcess(
         NOTREACHED() << "failed to start UI thread";
         return 1;
       }
+      thread->WaitUntilThreadStarted();
       ui_thread_.swap(thread);
     }