diff --git a/remote_desk_gui/main.cpp b/remote_desk_gui/main.cpp
index 0727dec..a1a28c3 100644
--- a/remote_desk_gui/main.cpp
+++ b/remote_desk_gui/main.cpp
@@ -218,12 +218,14 @@ inline int ProcessMouseKeyEven(SDL_Event &ev) {
 void ReceiveVideoBuffer(const char *data, size_t size, const char *user_id,
                         size_t user_id_size) {
   // std::cout << "Receive: [" << user_id << "] " << std::endl;
-  memcpy(dst_buffer, data, size);
+  if (joined) {
+    memcpy(dst_buffer, data, size);
 
-  SDL_Event event;
-  event.type = REFRESH_EVENT;
-  SDL_PushEvent(&event);
-  received_frame = true;
+    SDL_Event event;
+    event.type = REFRESH_EVENT;
+    SDL_PushEvent(&event);
+    received_frame = true;
+  }
 }
 
 void ReceiveAudioBuffer(const char *data, size_t size, const char *user_id,