diff --git a/src/capture/capture_base.cpp b/src/capture/capture_base.cpp
index c53114be9f0779ad4fce5ea845a39cc173608949..0ee44db531dc690d196c31958e343d683f8c56be 100644
--- a/src/capture/capture_base.cpp
+++ b/src/capture/capture_base.cpp
@@ -219,7 +219,7 @@ void CaptureBase::setProblem(ProblemPtr _problem)
     if (_problem == nullptr || _problem == this->getProblem())
         return;
 
-    assert(getFrame() and getFrame()->isKey());
+    assert(getFrame() && "Cannot set problem: Capture has no Frame!");
 
     NodeBase::setProblem(_problem);
     registerNewStateBlocks(_problem);