diff --git a/src/ComputeForce.cu b/src/ComputeForce.cu
index d7f055c3d4c495acc01698df6b60304cdac95705..3d025880ee0eca499fd1811339d0e7dc972dd5a6 100644
--- a/src/ComputeForce.cu
+++ b/src/ComputeForce.cu
@@ -136,6 +136,8 @@ ComputeForce::ComputeForce(const Configuration& c, const int numReplicas = 1) :
 		}
 	}
 	
+	restraintIds_d = NULL;
+
 	//Calculate the number of blocks the grid should contain
 	gridSize =  num / NUM_THREADS + 1;