diff --git a/gfx/layers/ipc/ImageBridgeParent.cpp b/gfx/layers/ipc/ImageBridgeParent.cpp
index 19b74a9746f2..264ff38466a9 100644
--- a/gfx/layers/ipc/ImageBridgeParent.cpp
+++ b/gfx/layers/ipc/ImageBridgeParent.cpp
@@ -360,7 +360,7 @@ already_AddRefed<ImageBridgeParent> ImageBridgeParent::GetInstance(
   MonitorAutoLock lock(*sImageBridgesLock);
   ImageBridgeMap::const_iterator i = sImageBridges.find(aId);
   if (i == sImageBridges.end()) {
-    NS_ASSERTION(false, "Cannot find image bridge for process!");
+    NS_WARNING("Cannot find image bridge for process!");
     return nullptr;
   }
   RefPtr<ImageBridgeParent> bridge = i->second;