diff --git a/src/main/java/de/stups/probkodkod/NonIncrementalSolverSolutionIterator.java b/src/main/java/de/stups/probkodkod/NonIncrementalSolverSolutionIterator.java
index d5b606cb8ee58937f244f311b5c4752ad14a983c..afbd0ac09f5705bf0fdc23620c56258b1bd6d8d6 100644
--- a/src/main/java/de/stups/probkodkod/NonIncrementalSolverSolutionIterator.java
+++ b/src/main/java/de/stups/probkodkod/NonIncrementalSolverSolutionIterator.java
@@ -21,6 +21,7 @@ public class NonIncrementalSolverSolutionIterator implements Iterator<Solution>
 	@Override
 	public Solution next() {
 		if (!returned) {
+			returned = true;
 			return sol;
 		}
 		throw new RuntimeException("second solution of non-incremental solver requested");