diff --git a/src/composite.cpp b/src/composite.cpp
index 883f76c1a0..734e2fe096 100644
--- a/src/composite.cpp
+++ b/src/composite.cpp
@@ -289,6 +289,9 @@ bool Compositor::setupStart()
 
         if (stop) {
             break;
+        } else if (qEnvironmentVariableIsSet("KWIN_COMPOSE")) {
+            qCCritical(KWIN_CORE) << "Could not fulfill the requested compositing mode in KWIN_COMPOSE:" << type << ". Exiting.";
+            qApp->quit();
         }
     }