diff --git a/src/system.c b/src/system.c
index f9984d1..e5299ca 100644
--- a/src/system.c
+++ b/src/system.c
@@ -661,11 +661,14 @@ roleInstance (const System sys, const Protocol protocol, const Role role,
   /* erase any substitutions in the role definition, as they are now copied */
   termlistSubstReset (role->variables);
 
-  /* Determine symmetric run */
-  runs[rid].prevSymmRun = staticRunSymmetry (sys, rid);	// symmetry reduction static analysis
+  if (sys->engine == POR_ENGINE)
+    {
+      /* Determine symmetric run */
+      runs[rid].prevSymmRun = staticRunSymmetry (sys, rid);	// symmetry reduction static analysis
 
-  /* Determine first read with variables besides agents */
-  runs[rid].firstNonAgentRead = firstNonAgentRead (sys, rid);	// symmetry reduction type II
+      /* Determine first read with variables besides agents */
+      runs[rid].firstNonAgentRead = firstNonAgentRead (sys, rid);	// symmetry reduction type II
+    }
 }