diff --git a/de.prob.core/src/de/prob/core/command/ActivateUnitPluginCommand.java b/de.prob.core/src/de/prob/core/command/ActivateUnitPluginCommand.java
index c75c3a7b52f8d0a26aeee2943ccf39905739712f..5071e60e1f179908b6a1d438c12b818c408407ac 100644
--- a/de.prob.core/src/de/prob/core/command/ActivateUnitPluginCommand.java
+++ b/de.prob.core/src/de/prob/core/command/ActivateUnitPluginCommand.java
@@ -48,7 +48,9 @@ public class ActivateUnitPluginCommand implements IComposableCommand {
 		}
 
 		public void writeCommand(final IPrologTermOutput pto) {
-			pto.openTerm("activate_plugin(units)").closeTerm();
+			pto.openTerm("activate_plugin");
+			pto.printAtom("units");
+			pto.closeTerm();
 		}
 	}